Transactions of the Royal Society of Edinburgh: Earth Sciences, 93, 333±353, 2003 (for 2002)
Evolutionary relationships of the Sparidae (Teleostei: Percoidei): integrating fossil and Recent data Julia J. Day ABSTRACT: The Eocene sparid fauna (Teleostei: Percoidei) from Monte Bolca, Italy and from the London Clay, U.K. is revised based on re-examination of the type material and phylogenetic analyses of primarily osteological data. Two phylogenetic analyses, one of the Eocene taxa and a combined analysis of fossil and extant taxa, were performed. The addition of fossils to the extant data greatly increased numbers of most parsimonious trees, destabilising and obscuring basal relationships within the Sparidae. Combination of the data from fossil and extant data also affected relationships among the fossil taxa, changing some from those recovered using fossil data alone and destabilising others. Successive approximations character weighting supported the inclusion of the Eocene taxa within a monophyletic Sparidae. The genus Sparnodus, as previously conceived, is paraphyletic and is partitioned to remove the paraphyly. Five monotypic genera are recognised, including three new genera, Abromasta, Ellaserrata and Pseudosparnodus. Inclusion of the fossils in the phylogenetic analysis implies a minimum age of origin for the Sparidae of 55 Ma with most Recent sparid fauna in place no later than the Miocene, and provides further evidence that the diversi®cation of feeding strategies occurred early on in the evolutionary history of the group.
KEY WORDS: homoplasy, missing data, morphology, phylogeny, sparids.
The family Sparidae are percoid ®sh that include 100 extant species grouped within 29 genera (Nelson 1994). They have a broad geographical distribution, inhabiting coastal waters of tropical to temperate zones. Until recently, little was known about their phylogenetic relationships; however, morphological (Day 2002) and molecular (Hanel & Sturmbauer 2000) studies have begun to address sparid interrelationships. A number of morphological studies (Akazaki 1962; Johnson 1980; Bianchi 1984; Rosen & Patterson 1990; Day 2002) have provided information about osteological variation within extant sparids that can be directly applied to the understanding of fossil sparids. Current diagnoses of the Sparidae are based on external morphological characters, such as the number of hard versus soft dorsal and anal ®n-rays and features of the dentition (Bauchot & Hureau 1986; Smith & Smith 1986). Variation in dentition (of the oral jaws) serves as the main criterion in the diagnosis of the four subfamilies of Sparidae (Sparinae; Denticinae; Boopsinae; Pagellinae: Smith & Smith 1986). However, molecular phylogenetic studies (Hanel & Sturmbauer 2000) and morphological studies (Day 2000, 2002) indicate that some of these subfamilies are paraphyletic. Dentition has also served as an important source of characters for the de®nition of many percoid groups, but appears to be particularly homoplastic within the Percoidei (Johnson 1980). While dentition does not provide a satisfactory basis for higher-level taxonomy within the Sparidae (Day 2002), some tooth morphologies can be useful in identifying certain genera. Previous studies of Eocene presumed sparid taxa (Agassiz 1835±44) give little or no justi®cation for their assignment to the Sparidae. Indeed, until Akazaki (1962), no diagnostic osteological features of sparids had been identi®ed. In reconsidering putative fossil sparids, a rigorous taxonomic approach needs to be applied to these taxa in the ®rst instance to support or deny their membership of the family.
Phylogenetic analysis (Day 2002), using predominantly osteological characters of extant taxa, found four synapomorphies that support a monophyletic Sparidae: three or more openings of the pars jugularis; a specialised premaxillary± maxillary articulation; a post-pelvic process that is reduced or absent; and infraorbitals I and II that are deeper than wide. These characters can be used to identify fossil sparids and furthermore, represent different anatomical systems which may be useful when considering partially preserved specimens. However, of the four characters some will undoubtedly have a higher preservation potential than others. Day’s (2002) study of extant sparids allows a phylogenetic perspective on the taxonomy of fossil sparids to be adopted. The inclusion of fossils within a Recent data matrix allows the evolutionary history of this group to be examined. The aims of the present study are to redescribe and revise Eocene sparids in the light of phylogenetic analysis of combined data from fossil and extant sparids and to assess the effects of fossils on hypotheses of extant sparid relationships.
1. Historical review The fossil record of sparids is sparse compared to the diversity of extant taxa found today. Articulated remains are known from several formations: the London Clay Formation (Eocene, Ypresian) of SE England; the Monte Bolca Formation (Eocene, Lutetian) of NE Italy; the Sarmatian±Pannonian sediments (Late Tertiary), Pinarhisar, Thrakia, Turkey; the SaheÂlien Formation (Miocene, Messinian) of central Oman; and the Marecchia River deposit (Lower and Middle Pliocene) of eastern central Italy. Articulated fossils from the formations mentioned above are a fairly common component of the respective ichnofaunas. Isolated teeth, particularly from durophagous sparids, are regarded as common vertebrate
JULIA J. DAY
remains of temperate shallow marine Neogene deposits (Otero 1997; Day 1999). Seven monotypic genera are identi®ed from the Eocene: Abromasta, Ellaserrata, Sciaenurus, Pseudosparnodus, Sparnodus, Dentex and Ctenodentex. Apart from the extant genus Dentex, none of these taxa have been recorded in younger deposits. Sciaenurus from the London Clay is probably the oldest representative of the family, as the Bolca deposits are now thought to be Lutetian (Harland et al. 1990), and are therefore slightly younger than the London Clay. The identi®cation of fossil species using the same criteria that are applied to extant species, such as colour pattern, scale distribution, gill-raker and ®n-ray counts, is not always possible and suggests that the described fossil genera may not all be truly monotypic. Arambourg (1927) described eight species of sparid, from the Upper Miocene of Oman, which he assigned to eight of the living sparid genera. The criteria by which many of these species are recognised are dif®cult to evaluate, and revision is desirable. Unfortunately, of Arambourg’s species only the holotype of Diplodus oranensis was available for study. Observations from photographs (Arambourg 1927, pls 19±25) and accompanying text, indicate that the species assigned to Boops, Crenidens, Dentex and Pagrus display some of the characteristics of these modern genera. This is also true for the specimen assigned to Boops sp. from the Marecchia river deposits of the Pliocene of Italy (Sorbini 1987, p. 80, ®g. 2) and Sparus sp. from the Miocene of South Australia (Frickhinger 1991, p. 836). These features include jaw morphology and dentition, in addition to the overall shape of the braincase. There is little evidence to suggest that the specimens assigned to the genus Pagellus (Arambourg 1927, pl. 20, ®g. 19, pl. 22, ®gs 2,3, pl. 25, ®g. 2) are of sparid af®nity. Furthermore, isolated teeth assigned to Sparus could equally be from Pagrus. The identi®cation of Sparus intermedius from late Tertiary deposits of Turkey is dubious due to the poor preservation of this specimen. According to the ®gures published by RuÈckert-UÈlkuÈmen (1995, p. 83, pl. 4), even the familiar assignment of this species within the Sparidae was not well substantiated.
2. Geological setting Monte Bolca ®shes form one of the earliest de®ned coral reef ®sh assemblage (Blot 1980; Sorbini 1983; Bellwood 1996). The ®shes found in this assemblage include members of almost all Recent coral reef and reef-associated families. Furthermore, for most families the diversity of species is matched by numerical abundance. The dominance of perciform ®shes in the Bolca assemblage is consistent with modern reef ichthyofaunas, but it also, uniquely, includes the last link to the Mesozoic era with one of the latest records of the extinct order Pycnodontiformes. It appears that by the early Tertiary the ®nal transition from non-perciform to perciform-dominated faunas had taken place (Bellwood 1996). For these reasons the Bolca assemblage provides a unique insight into the evolution of coral reef and reef-associated ®shes. Monte Bolca deposits are marine limestones, usually dated as topmost Ypresian (e.g. Blot 1980), based upon nannoplankton. This places the beds in the NP14 zone of Discoaster sublodoensis covering a time period from 49.5±47.2 Ma (Neal 1996). Harland et al. (1990) place NP14 as lowermost Lutetian, which is accepted by Patterson (1993). The Bolca deposits are thought to have been located in what was the centre of the Tethys Sea (Bellwood 1996). The London Clay was deposited during the Early Eocene, Ypresian (King 1981) at a time of
high sea-level stand (Huggett & Gale 1998). During this time SE England was covered by a shallow shelf sea, with seawater temperatures in the high 20 8s (Buchardt 1978). The shores of the London Clay sea supported a subtropical ¯ora (Collinson 1983). The exact placement of the vertebrate material from Sheppey is uncertain, as much of the collected material was not found in situ. However, some specimens have been collected from nodule layers 5±10 m above the base of the exposed section in Division D, P6 B (King 1981, p. 52, ®g. 15) and it is reasonable to suppose that most museum specimens are from similar horizons. Division D comprises a dominantly homogenous clay/silt lithology, with silt and sand partings at some levels in addition to beds of sandy silt (King 1981).
3. Material and methods Although pigmentation can be preserved in some of the Bolca specimens, this material rarely preserves details of braincase anatomy. Sutures on the braincase are generally dif®cult to observe. Thus, while the overall skeleton remains relatively intact, complex three-dimensional structures such as the braincase are usually destroyed. The gill arches are not suf®ciently well preserved in any specimens examined for them to be fully reconstructed. However, BMNH 44867 has been acid prepared and yields far more information than the other specimens that have not been prepared similarly. For this reason BMNH 44867 forms the basis of the description of Sparnodus vulgaris. The following sparid genera are revised in this study (yindicates fossil taxa) yAbromasta, yEllaserrata, ySciaenurus, yPseudosparnodus, ySparnodus. These taxa, plus yDiplodus oranensis and the extant sparids Dentex, Argyrozona, Porocostoma, Polysteganus, Chrysoblephus, Evynnis, Cheimerus, Boopsoidea, Pagellus, Pagrus, Stenotomus, Lithognathus, Spondyliosoma, Spicara, Oblada, Sarpa, Boops, Pachymetopon, Polyamblyodon, Lagodon, Crenidens, Sparodon, Diplodus, Rhabdosargus, Acanthopagrus, Archosargus, Calamus, Sparus and Argyrops are included in the phylogenetic analyses. Further extant taxa Centropomus, Lutjanus, Haemulon, Nemipterus and Lethrinus are included as outgroup taxa. Repository abbreviations. MCSNV: Museo Civico di Storia Naturale, Verona, Italy; BMNH: The Natural History Museum, London; MNHN: MuseÂum National d’Histoire Naturelle, Paris.
3.1. Phylogenetic methods Day (2002) developed a data set of 87 characters scored for 29 extant sparids and a range of outgroup taxa. This provides a framework for investigating the phylogenetic relationships of fossil sparids and establishing a minimum age of origin of clades. Two analyses were performed: the ®rst includes only Eocene fossil taxa, while the second, a combined analysis, includes fossil and extant taxa. The Miocene taxon Diplodus oranensis was included in the second analysis to test whether it and its extant congeners are monophyletic and to obtain further information on the minimum age of origin of clades. As the extant data set was shown to contain considerable homoplasy (Day 2002), the fossil analysis was performed primarily to compare the relationships of the fossil taxa with the outcome obtained from their inclusion within the extant data matrix. The extant taxon Lutjanus was used as an outgroup in the fossil analysis. Phylogenetic analysis was performed using PAUP¤ 4.0 (Swofford 1998). Branch and bound searches were implemented for the fossil matrices, while
EVOLUTIONARY RELATIONSHIPS OF THE SPARIDAE
a heuristic search using tree±bisection±reconnection branch swapping was performed for the combined matrix. The level of support was assessed with Bremer (decay) indices (Bremer 1988, 1994), determined by constraint analyses, and bootstrap values (Felsenstein 1985) using 1000 replicates. Parsimony (Faith & Cranston 1991) and pairwise incompatibilty (Wilkinson 2001) permutation tail probability tests (PTP) used 100 and 1000 replications respectively. A posteriori or successive approximation reweighting (Farris 1969) was performed using rescaled consistency indices and the best ®ts of characters.
4. Systematic palaeontology Division Teleostei sensu Nelson, 1969 Order Perciformes Bleeker, 1859 Suborder Percoidei Bleeker, 1859 Superfamily Sparoidea Johnson, 1980 Family Sparidae Bonaparte, 1831 Genus Sparnodus Agassiz, 1839 Type species. Sparnodus vulgaris de Blainville, 1818, p. 349. Diagnosis. Distinguished from other Eocene sparids by a robust jaw with large, conical teeth. Ethmoid dorsal margin is depressed directly anterior to the ethmoid±frontal suture. Deep-bodied form with a length to width ratio of 3:1. The supraneural formula appears to be 0=0 ‡ 0=2 ‡ 1=1; and the anterodorsal processes of the supraneurals overlap. Hypurals are separate. Caudal ®n is of low aspect ratio. Formula of the dorsal ®n XII ‡ 9; anal ®n III ‡ 9: Remarks. The taxonomic history of Sparnodus and its type species is complex, with many names having been applied to the type species. The consensus since Woodward (1901) is that there are three species: Sparnodus vulgaris, S. microstomus and S. elongatus. Sparnodus elongatus is diagnosed on the basis of its more slender body form, but an examination of the holotype (MNHN 10804, Fig. 2) revealed no substantial difference between this species and Sparnodus vulgaris (Fig. 1). Therefore, Sparnodus elongatus is regarded here as a junior synonym. However, some specimens labelled as Sparnodus elongatus are very clearly different from Sparnodus vulgaris and are here assigned to a new genus Ellaserrata. The inclusion of Sparnodus microstomus in this genus is also problematic. There are distinct differences in the jaw morphology between Sparnodus microstomus and Sparnodus vulgaris; in particular, the morphology of the upper jaws differs more than would be expected for species-level diagnosis. Recent species are de®ned using external features such as ®n-ray counts or colour (e.g. Fischer 1973, 1978; Fischer & Bianchi 1984; Fischer & Whitehead 1974; Fischer et al. 1981). Furthermore, the phylogenetic analysis (section 5) indicates that Sparnodus as previously conceived is paraphyletic. Therefore S. microstomus is referred to the new genus, Pseudosparnodus, to remove the paraphyly. Sparnodus vulgaris (de Blainville, 1818) (Figs 1,2) 1796 1796 1796 1796 1796 1818 1835
Sparus macrophthalmus Volta, p. 247, pl. 60. Cyprinus Volta, pl. 73. Sparus dentex Volta, p. 62, pl. 13, ®g. 1. Sparus sargus Volta, p. 76, pl 17, ®g. 1. Sparus erythrinus Volta, p. 249, pl. 60, ®g. 3. Sparus vulgaris de Blainville, p. 349. Sparnodus macrophthamus Agassiz, p. 300 (nomen nudum).
1835 1835 1835 1836 1839 1839 1839 1839 1839 1876 1876 1886 1901 1911 1980
Sparnodus ovalis Agassiz, p. 300 (nomen nudum). Sparnodus altivelis Agassiz, p. 300 (nomen nudum). Sparnodus micracanthus Agassiz, p. 164, pl. 28, ®g. 2. Sparnodus elongatus Agassiz, p. 165, pl. 28, ®g. 1. Serranus ventralis Agassiz, p. 104, pl. 23b. Sparnodus macrophthamus Agassiz, p. 158, pl. 28, ®g. 3. Sparnodus ovalis Agassiz, p. 161, pl. 29, ®g. 2. Sparnodus altivelis Agassiz, p. 162, pl. 29, ®g. 3. Sparnodus micracanthus Agassiz, p. 164, pl. 28, ®g. 2. Sparnodus ovalis Bassani, p. 177. Sparnodus micracanthus Bassani, p. 177. Sparnodus lethriniformis Szajnocha, p. 270, pl. 1, ®g. 1. Sparnodus macrophthamus Woodward, p. 525. Sparnodus vulgaris (de Blainville); Eastman, p. 377. ®g. 2. Sparnodus vulgaris Blot, p. 372.
Holotype. MNHN 10796/10797 (part and counterpart), skeleton preserved in limestone matrix. Type locality and horizon. Lutetian, Lower Middle Eocene, Monte Bolca, Verona, Italy. Diagnosis. The diagnosis is the same as for the genus (see above). Additional material examined. MNHN 10804/10803, 10805, 10789/10790; BMNH 44867; MCSNV I.G 24547, II P.136. Description. Braincase. The braincase is triangular in lateral view (Fig. 1). The most prominent feature is the large occipital crest, which covers over half of the total length of the braincase. The ethmoid region or snout forms approximately one-third of the total braincase length. The edentulous vomer has a posterior shaft that terminates level to the anterior margin of the frontals. The vomer and ethmoid form a dorsal medial crest, while a shallow fossa for the ascending process of the premaxilla is present along the posterior ethmoid (Fig. 1c; f.as.p.pm). The lateral ethmoids are expanded posteriorly forming a preorbital ¯ange, the dorsal margin of which contains a large triangular-shaped fossa (fpo), characteristic of the superfamily Sparoidea. A laterally inclined facet of the lateral ethmoids provides the articulation surface for the maxillary process of the palatine. The ventral margin of the parasphenoid forms a narrow carina. The otico±occipital region of the parasphenoid bears a ventral stalk-like process, which is probably for the insertion of the m. adductor arcus palatini (Fig. 1c; ap). In MCSNV P265, a weakly developed pharyngeal apophysis is situated directly posterior to the process for the m. adductor arcus palatini. The parasphenoid in this region is dorsally inclined at 208. The frontals protrude anteriorly, and are inclined anterodorsally at 308. They form the anterior third of the frontal crest, in addition to the lateral and medial walls and the anteriormost part of the ¯oor of the post-temporal fossa. A series of pores perforate the dorsolateral surface of the frontals. These are assumed to be openings for branches of the laterosensory canal. Anteriorly, a shallow sulcus is assumed to connect to one of the pores of the laterosensory canal, as observed on an extant neurocranium of Lithognathus mormyrus BMNH 1855.9.19. The supraoccipital forms a large dorsal occipital crest, the length of which is greater than the height, separating the parietals throughout their length. Anteriorly, the crest extends to the anterior third of the orbit, and covers more than half of the total braincase length. A posterior dorsally convex ridge on the lateral face of the crest presumably strengthens such a large area of bone. The spina occipitalis extends ventrally between
JULIA J. DAY
Figure 1 Sparnodus vulgaris (de Blainville, 1818) (holotype) Eocene, Monte Bolca, Italy: (a) MNHN 10796/ MCSNV 265 (part), image reversed; (b) acid-prepared specimen of Sparnodus vulgaris, BMNH 44867; (c) camera lucida drawing of the cranium. For abbreviations, see Section 8. Scale bars represent 10 mm.
EVOLUTIONARY RELATIONSHIPS OF THE SPARIDAE
Figure 2 Sparnodus vulgaris (de Blainville, 1818) Eocene, Monte Bolca, Italy. Holotype of `Sparnodus elongatus’ (Agassiz, 1836) MNHN 10804/MCSNV 268. Scale bar represents 10 mm.
the epiotic and exoccipitals to the dorsal margin of the foramen magnum. The epiotic forms the posterodorsal region of the skull. In MCSNV P143 a lateral projection is partially visible and may be interpreted as the fossa for the articulation of the dorsal process of the post-temporal, but provides no further information as the posterior margin of this bone is unclear. The epiotic also forms the posterior part of the medial wall of the post-temporal fossa and the posterior third of the frontal crest. A small parietal forms the central third of the frontal crest and the lateral wall of the post-temporal fossa. The pterotic forms the posterior part of the ¯oor and the medial wall of the post-temporal fossa, the posterior third of the pterotic crest and posterior parts of the dilatator fossa and the hyomandibular facets. The almost conical post-temporal fossa is unroofed and extends to a third of the total length of the skull. The laterosensory canal enters the pterotic through a large pore at the posterior extremity of the crest and subsequently perforates the crest along its length with smaller pores. The posterior margin of the pterotic crest forms a posterodorsal depression for the articulation of the posttemporal ventral process. The sphenotic forms the posterolateral wall of the orbit, the anterior hyomandibular facet, the anterior part of the dilatator fossa and the central third of the medial wall of the posttemporal fossa. The large triangular dilatator fossa formed from the sphenotic and pterotic, extends anteriorly over the posterior third of the orbit, and appears to penetrate the frontals. In MCSNV P143 the dilatator fossa seems to pierce the anterior wall of the sphenotic, as in some extant sparids (e.g. Diplodus), although this is not clear on other specimens. The pars jugularis of the trigemino-facialis chamber is incompletely preserved. Two hyomandibular facets lie directly below the dilatator fossa: one facet on the sphenotic, the other on the pterotic. These facets are interpreted from internal moulds and appear to be of a similar size. Other features preserved as internal moulds include a circular fossa in the basioccipital, which is probably the attachment site for Baudelot’s ligament, and a single foramen in the exoccipital. This foramen may have transmitted both the vagus (X) and glossopharyngeal nerves (IX), although a separate foramen for the glossopharyngeal may have penetrated the poorly preserved bone anterior to this foramen.
Infraorbital region. In MCSNV P143 there are six infraorbital bones. Infraorbitals I and II are considerably larger than the succeeding bones and are deeper than wide. The ventral margin of infraorbitals I and II cover much of the maxilla. On the medial margin of the third bone a welldeveloped subocular shelf extends posteromedially. The remaining infraorbitals are rod-like and appear to decrease in length posteriorly. Jaws. The premaxilla is characterised by an alveolar process longer than the ascending process. In MCSNV P143 the narrow, tapering alveolar process has a convex dorsal margin, but no prominent maxillary process. The articulation of the premaxilla and maxilla is typical of extant sparids and is interpreted as being derived compared to other percoids (Day 2002, ®g. 3G). The fusion of the articular process with the ascending process in S. vulgaris is also a feature observed in extant sparids, as well as the sparoid family Lethrinidae (Johnson 1980). The premaxilla bears a single row of conical teeth, which gradually decrease in size posteriorly. The maxilla has a straight dorsal margin with a low anterodorsal crest. Rosen & Patterson (1990) consider this con®guration as a primitive percomorph character state. The palatine sulcus of the maxilla is short and does not extend as far as the anterior margin of the ascending process of the premaxilla. A small process is present on the anterolateral margin of this sulcus (Fig. 1c; ps). The maxilla is expanded posteroventrally extending well beyond these margins of the premaxilla. The dentary is of similar dimensions as in the living sparid genus Pagellus (BMNH 1983.10.11) and has a narrow coronoid process inclined at a low angle. The symphyseal process (Fig. 1c; psym) extends to approximately a quarter of the total length of the ventral margin. The laterosensory system of the mandible is represented by a single row of pores. The articular is only partially preserved, but the lateral margin of the articular fossa is concave. The quadrate facet is formed entirely by the articular, while the angular forms the posteroventral corner of the mandible. A descending process extends to the ventral margin of the dentary. The teeth in the dentary are similar to those described in the upper jaw. Hyo-palatine bones. The hyomandibula is double-headed and is de¯ected anteriorly. On the lateral face of the hyomandibula, the preoperculum rests against a vertical crest. The hyomandibula articulates with the operculum via
JULIA J. DAY
a posterior process. The symplectic (Fig. 1c; sym) is a rod-like bone that is dorsally expanded, lying in a sulcus on the medial face of the quadrate. The quadrate is triangular, and articulates with the articular via a double condyle. The ventral margin of the quadrate overlaps the ventral branch of the preoperculum. The ectopterygoid is bent through 508 and is sutured to the quadrate anterior margin. The bone tapers ventrally, but does not extend as far as the articular condyle of the quadrate. Posteriorly, the ectopterygoid dorsal margin lies against the endopterygoid, while anteriorly it is sutured to the palatine. The metapterygoid is a large triangular bone that meets the hyomandibular posteriorly. The metapterygoid anterior margin partly contacts the endopterygoid. A fontanelle, that would have contained cartilage, separates these bones from the quadrate. The endopterygoid is a small triangular bone, that contacts the ectopterygoid anteriorly and the metapterygoid posteriorly. The palatine is large and robust. The dorsally convex palatine maxillary process (Fig. 1c; mx.p) extends beyond the end of the vomer and is medially de¯ected. This process articulates with the lateral ethmoids via a laterally orientated facet, similar to the condition observed in Dentex. A posterior process extends from the lateral ethmoid facet. Posteroventrally the palatine contacts the ectopterygoid. Opercular bones and lower part of the hyoid arch. The preoperculum is bent through about 408. The ventral branch is shorter than the dorsal branch and lies lateral to the posteroventral margin of the quadrate. The narrower dorsal branch contacts the vertical ridge on the lateral face of the hyomandibular. The surface of the preoperculum is ornamented with ridges along the posterior margin of the angle. The operculum is a large triangular bone that becomes thicker towards the anterior margin. The interoperculum lies medial to the preoperculum, whilst the suboperculum is medial to the operculum dorsally and the interoperculum anteriorly. Remains of the hyoid arch and the branchiostegal rays are preserved in most specimens, although there is little useful information to recover. The hyoid arch in MCSNV P143 is short, compared to Dentex for example. The anterior part of the ceratohyal and hypohyals are expanded, although the latter bones are not well preserved. There are six acinaciform branchiostegal rays. The anterior four are large and attach to the ceratohyal, while the two posterior rays are distinctly smaller. The placement of the ®fth ray is unclear; it either attaches to the interspace between the ceratohyal and the epihyal, or to the epihyal. The posterior ray attaches directly to the epihyal. The basihyal is narrow and toothless. Pectoral girdle and ®n. The pectoral girdle is only partially preserved. The dorsal process of the post-temporal is longer than the ventral process, articulating with a depression on the dorsal face of a posterior projection of the epiotic, while the latter process articulates with the pterotic. A foramen for the lateral line canal is situated below the junction of the dorsal and ventral limbs of the post-temporal. The supracleithrum is blade-shaped and thickened anteriorly. Dorsally this bone presumably articulated with the post-temporal. The ventral tip of the supercleithrum lies lateral to the cleithrum. The ventral limb of the cleithrum is inclined anteriorly at about 808, and is about twice as long as the dorsal limb. The anterior process of the coracoid is slender and attaches to the cleithrum. The posterior margin of the scapula and coracoid are only partially preserved. There are four pectoral radials. The ventral-most radial is deeper than the rest and articulates against the interspace between the scapula and coracoid, whereas the three uppermost radials articulate with the scapula. The ventral postcleithrum is long and slender as in Dentex. The pectoral ®n consists of 14 rays.
Pelvic girdle and ®n. The posterior margin of the pelvic girdle is level with the second vertebra and intersects the pectoral girdle at approximately 658. The ®n is large, with a posterior margin that extends below the last abdominal vertebra. Dorsal and anal ®ns. There are 10 ®n-spines and 9 branched rays in the dorsal ®n of BMNH 44867. The ®rst radial supports two supernumerary ®n-spines. Three supraneurals are present. The dorsal ®n formula appears to be 0=0 ‡ 0=2 ‡ 1=1 (see Johnson 1984 for de®nition of formula). The supraneurals are expanded anterodorsally and each forms a process that overlies the posteriormost part of the preceding one. The process of the ®rst supraneural does not overhang the occipital crest as observed in some extant sparids e.g. Calamus. The anal ®n contains three ®n-spines, which is assumed to be the primitive condition in percoids (Johnson 1984). There are also two supernumerary ®nspines that are associated with the ®rst radial. The ®rst radial is considerably larger than the others, extending to the haemal arch of the last abdominal vertebra, and is thickened anteriorly. Vertebral column and caudal skeleton. There are 24 vertebrae …10 ‡ 14†; including the urostyle, con®rming the observation of Agassiz (1835 in 1835±44, p. 155). The ®rst two vertebrae are anteroposteriorly compressed with lower neural spines. Poor preservation prevents description of the attachment of intermusculatures to the vertebrae. The caudal skeleton is complete, and has a similar arrangement to extant sparids (see Fujita 1990, pp. 320±27, ®gs 501±508). The hypurals are separate, whilst the hypurapophysis extends to the medial margin of hypural 2. The caudal ®n as in all extant sparids contains 9:8 principal rays. The ®n is large and has a shallow forked outline. There appear to be six to seven? procurrent rays above and below the respective principal rays. Pseudosparnodus gen. nov. Diagnosis. A deep-bodied Eocene sparid, with a standard length-to-depth ratio of 2:1 giving it an oval shape in lateral aspect. Frontals inclined at 508 from the horizontal plane. Reduced ethmoid±vomerine region. Length of occipital crest equal to height. Jaws with a low sub-terminal maxillary crest. The premaxillary ascending process is more than half the length of the alveolar process, with the articular process fused to the premaxillary ascending process. Dentition consists of small caniniform teeth …< 2 mm† along the occlusal jaw margin. Formula of the dorsal ®n XII ‡ 9; anal ®n III ‡ 9: Shallowly forked caudal ®n. Etymology. Pseudo (Greek) for false, is used as a pre®x to indicate its original referral to Sparnodus. Type species. Serranus microstomus Agassiz, 1835, p. 300. Pseudosparnodus microstomus (Agassiz, 1835) (Fig. 3) 1796 Sparus brama Volta, p. 187, 45, ®g. 3 (error, an extant species). 1818 Sparus brana ¡ Sparus vulgaris de Blainville, p. 350. 1835 Serranus microstomus Agassiz, p. 300 (nomen nudum). 1835 Serranus occipitalis Agassiz, p. 102, pl. 23. 1835 Dentex breviceps Agassiz, p. 300 (nomen nudum). 1839 Serranus microstomus Agassiz, p. 100, pl. 23a. 1839 Dentex breviceps Agassiz, p. 149, pl. 27, ®gs 3, 4. 1901 Sparnodus microstomus Woodward, p. 527. 1980 Sparnodus microstomus Blot, p. 372. Holotype. MNHN 10729/10730 (part and counterpart), skeleton partially preserved in limestone matrix. Type locality and horizon. Lutetian, Lower Middle Eocene, Monte Bolca, Verona, Italy.
EVOLUTIONARY RELATIONSHIPS OF THE SPARIDAE
Diagnosis. As for the genus. Additional material examined. MCSNV T.886. Description. Due to poor preservation and lack of material of this specimen the following description offers little further information than the diagnosis. Much of the braincase, the palatine and the hyoid arches are not preserved. The triangular braincase is shorter than in Sparnodus vulgaris due to the reduction in length of the ethmoid± vomerine region. This region is considerably reduced as in Diplodus, and there appears to be a fossa for the premaxillary ascending process. The frontals are steeply inclined at 508 and appear to be nearly, but not totally, continuous in inclination to the occipital crest. The length of the occipital crest appears to be equal to the height. A preorbital fossa is present as is usual in sparid ®sh. The otico-occipital ventral margin of the braincase appears to be inclined so that the facets of the exoccipital condyles are orientated posteriorly. The parasphenoid carina is weakly developed. In MCSNV T.886 (Fig. 3b), the jaws are notably different to those of Sparnodusvulgaris (Fig. 1c). The following characteristics highlight these differences. The dorsal maxillary crest of the premaxilla is sub-terminal, rather than absent as described for S. vulgaris; however, it is not as prominent as in some extant forms e.g. Calamus. The sub-terminal maxillary crest appears to be a derived feature of extant sparids and implies that the jaw
articulation is specialised, although some sparids do not have this structure, but do possess the distal bifurcation of the maxilla representing the `specialised’ articulation of the upper jaw elements. The maxillary dorsal crest appears to be weakly developed, rather than the knob-like form described for S. vulgaris, although the maxillary palatine sulcus is short as in the latter species. It is hard to discern whether the length of the premaxillaryascendingprocess is shorter thanor equal in height to the alveolar process, as it is broken in this specimen. However, the premaxillary articular process is fused to the ascending process. The dentary appears to be similar to that of S. vulgaris. The dentition is caniniform and the teeth are reasonably uniform in size. A faint impression of the infraorbitals reveals that the ®rst two infraorbitals are deeper than wide. There appears to be no obvious ventral con¯uent ridge of the quadrate and preoperculum and the preoperculum posterior margin is smooth. The postcranium is reasonably well preserved and appears to be similar in morphology to S. vulgaris. Ellaserrata gen. nov. Diagnosis. An Eocene sparid distinguished by a serrated preoperculum. Elongate body with a length:depth ratio of approximately 4:1 in adult specimens. Widely spaced supra-
JULIA J. DAY
neurals. Ethmoid±vomerine dorsal crest. Dorsal maxillary crest is sub-terminal. Dentition consists of caniniform teeth that are fang-like anteriorly. Hypurals appear fused. Formulae for the dorsal and anal ®ns we X ‡ 10 and III ‡ 9; respectively. Etymology. From Ella (Latin) for small, while the suf®x scrratus (Latin) means serrated. The name is due to the small serrations along the posterior margin of the preoperculum, which are unique to this genus. Type species. Ellaserrata monksi sp. nov. Ellaserrata monksi. sp. nov. (Fig. 4) Perca radula Volta, p. 134, pl. 31, ®g. 1. Sparus chromis Volta, p. 138, pl. 32, ®g. 1. Sparus salpa Volta, p. 130, pl 56, ®g. 1. Sparnodus elongatus Eastman, p. 378, pl. 91, ®g. 3 and pl. 98. 1980 Sparnodus elongatus Blot, p. 372. 1796 1796 1796 1911
Holotype. BMNH P1938/3900 (part and counterpart), skeleton preserved in limestone matrix. Type locality and horizon. Lutetian, Lower Middle Eocene, Monte Bolca, Verona, Italy. Diagnosis. As for the genus. Etymology. After Neale Monks (Department of Paleontology, The Natural History Museum, London) Additional material examined. BMNH P6855, P3901, P1900.
Description. Braincase. The ethmoid±vomerine region is elongate, forming a third of the total length of the braincase. The posterior margin of the vomer is con¯uent with the frontal anterior margin. The ethmoid±vomerine dorsal margin forms a prominent crest and there appears to be no obvious fossa for the ascending process of the premaxilla as observed in S. vulgaris. The preorbital fossa is the typical triangular shape of extant sparids, but is smaller than in S. vulgaris. The frontals are smooth and inclined at 228, approximately 108 less than recorded for S. vulgaris. The occipital crest is greater in length than height, extending anteriorly to the posterior margin of the orbit, and is smaller than the one in S. vulgaris. The dilatator fossa extends anteriorly to a point level with the anterior margin of the occipital crest. The concave parasphenoid ventral margin deepens posteriorly, probably for the attachment of the m. adductor arcus palatini. The process for the m. adductor palatini and the pharyngeal apophysis of the basicranium are weakly developed when compared with extant sparids such as Calamus. The occipital condyles are orientated posteroventrally as the oticooccipital region of the parasphenoid is only slightly inclined from the horizontal plane. In BMNH P6855, a large foramen, probably for the vagus nerve, pierces the exoccipital. It is not obvious if there is a separate foramen for the glossopharyngeal nerve. Another foramen, probably for the n. spino-occipitalis, pierces the lateral margin of the occipital condyle, and a large fossa, which is probably for the attachment of Baudelot’s
EVOLUTIONARY RELATIONSHIPS OF THE SPARIDAE
ligament, is present in the lateroventral face of the basioccipital. Infraorbitals. Only infraorbitals I and II are preserved (Fig. 4b) and are both deeper than wide. These bones are ornamented with vertical ribbing and extend below the dorsal margin of the maxilla. Jaws. The jaws, in particular the mandible, are less robust than in S. vulgaris. The premaxillary ascending process is just over half the length of the alveolar process (Fig. 4b). The dorsal maxillary crest of the premaxilla is sub-terminal, although it is not as well developed as in some extant sparids (e.g. Diplodus). A single row of caniniform teeth occurs along the occlusal surface of the premaxilla (Fig. 4b). Larger recurved caniniform teeth are situated anterolaterally. Villiform teeth are also present along the medial margins of the jaws. A well-developed sub-terminal crest in extant sparids is often associated with a de¯ected maxilla that is bent through 60±908 in lateral view. However, the maxilla in Ellaserrata is straight, with a low dorsal crest. Posteriorly, the maxilla is expanded. The premaxilla articular process appears to be separate from the ascending process. The dentary is narrower dorsoventrally compared to S. vulgaris. The symphyseal process is short with a prominent ventral process. The lateral margin of the articular fossa is vshaped and deep. A third of the total length of the mandible is formed from the articular and angular. The dentition of the dentary is the same as that described for the premaxilla. The descending process of the articular extends to the ventral margin of the dentary. The angular is a small bone and forms the posteroventral corner of the mandible. The hyo-palatine bones. The palatine arch is only partially preserved, providing little information. The ventral margin of the quadrate forms a con¯uent ridge with the preoperculum as in S. vulgaris. This feature is not as prominent as in S. vulgaris as it ¯attens posteriorly. Opercular bones and lower part of the hyoid arch. The opercular series is similar to S. vulgaris. However, small serrations occur along the posteroventral margin of the preoperculum (Fig. 4b). The preoperculum is bent through 608. Only the branchiostegal rays are preserved, which number six. These are acinaciform in shape. Pectoral and pelvic girdle and ®ns. These structures are partially preserved; however, their morphology is not unusual when compared to other sparids. Dorsal and anal ®ns. Three supraneurals are widely spaced so that the anterodorsal projections do not overlap; however, the dorsal ®n formula cannot be deduced, as the neural spines are not preserved. It would appear that the formula of ®nspines versus rays is X/10 and III/9 in the dorsal and anal ®ns, respectively. The radial for the ®rst anal ®n is thickened anteriorly, but is not as robust as in S. vulgaris. Vertebral column and caudal skeleton. There are 24 vertebrae …10 ‡ 14†: The hypural plates 1±2, and 3±4 appear fused and the caudal ®n is moderately high aspect ratio (Fig. 4a). The number of principal rays is 9:8. Abromasta gen. nov. Diagnosis. A sparid ®sh distinguished by the strongly convex shape of the anterodorsal margin of the frontals, short ethmoid±vomerine region and exceptionally slender premaxillary alveolar and ascending processes. The frontals are cancellose in texture, and the occipital crest is equal in height and length. The maxillary dorsal crest is knob-like. The dentition consists of villiform teeth that cover the occlusal surface of the premaxilla and dentary. The hypurals appear fused and the caudal ®n is high aspect ratio.
Etymology. From Abro (Greek) for delicate, while the suf®x -masta (Greek) means mouth or jaws. Type species. Pagellus microdon Agassiz 1839, p. 152. Remarks. This ®sh is considered suf®ciently different from the extant genus Pagellus, to which it was formerly referred (Agassiz 1839 in 1835±44, p. 152), to warrant erection of a new genus. Abromasta most clearly differs from Pagellus on the basis of its jaw and tooth morphology. Pagellus has robust jaws associated with conical/molariform type dentition (see Description). Abromasta microdon (Agassiz, 1839) (Fig. 5) 1835 Pagellus microdon Agassiz, p. 300 (nomen nudum). 1839 Pagellus microdon Agassiz, p. 152, pl. 27, ®g. 1. 1980 Pagellus microdon Blot, p. 372. Holotype. MNHN 10784/10785 (part and counterpart), skeleton preserved in limestone matrix. Type locality and horizon. Lutetian, Lower Middle Eocene, Monte Bolca, Verona, Italy. Diagnosis. As for the genus. Additional material examined. MCSNV II 0.121, II 0.123, II 0.124, II 0.125, II 0.126, II 0.127, II 0.128, T83, T84; BMNH P62113. Description. Braincase. Much of the braincase morphology is only partially preserved. In lateral aspect the overall shape is short anteroposteriorly and deep dorsoventrally. The depth of the braincase (including the occipital crest) is nearly equal to the total length. The ethmoid±vomerine region is greatly reduced anteroposteriorly as observed in Diplodus, so that the posterior margin of the vomer is level with the anterior margin of the frontals and orbit. A depression along the dorsal margin of the ethmoid houses the ascending process of the premaxilla. The posterior wall of this fossa is steeply concave. A fossa in the preorbital ¯ange of the lateral ethmoids is triangular in outline as in all sparids. The frontal dorsal margin prior to the anterior margin of the occipital crest is strongly convex. This region of the frontals is strongly textured with a cancellose structure, as is the anterior base of the occipital crest. The height and length of the occipital crest are approximately equal. Posteriorly, the occipital ridge is almost vertical. In MNHN 10784 and 10785 (Fig. 5a,b), dorsal to the crest and supraneurals, the body outline is expanded anterodorsally and is interpreted as a ¯eshy protuberance. The otico-occipital ventral margin of the braincase is steeply inclined at 408. Anteriorly, the parasphenoid is narrow, widening posteriorly probably for the attachment of the m. adductor arcus palatini. The process for the m. adductor arcus palatini also appears to be present. In BMNH P62113 the posterior part of the nasal is preserved as the usual tubular bone. Judging by the length of the snout, the nasals would have been short compared to S. vulgaris. Jaws. The jaws have an overall delicate morphology, particularly the upper jaw, which differs from the extant genus Pagellus on the basis of the considerably more slender premaxillary alveolar and ascending processes. The jaws in Abromasta are often partially preserved and disarticulated (Fig. 5a,b). The premaxillary ascending process is shorter than the alveolar process, which has no obvious dorsal maxillary crest and tapers posteroventrally. The dentition is of villiform type, which is notably different to the large conical and molariform teeth of Pagellus. The articular process appears to be fused to the ascending process, although the distinction is
JULIA J. DAY
Figure 5 Abromasta microdon (Agassiz, 1839), Eocene, Monte Bolca, Italy: (a) holotype MNHN 10785/MCSNV 47 (part); (b) MNHN 10784/MCSNV 46 (counterpart). Scale bars represent 10 mm.
somewhat unclear. The maxilla is also slender. In BMNH P62113 the palatine sulcus of the maxilla appears to extend to the premaxilla anterior margin. The posterior ramus of the maxilla is bent through approximately 408 and is enlarged posteriorly. The dentary is elongate. It is much narrower dorsoventrally than anteroposteriorly, tapering signi®cantly to a narrow symphysis only several millimetres in depth. The articular fossa is also deep and has a v-shaped lateral margin that extends halfway into the dentary. The articular descending process appears to extend below the ventral margin of the dentary and the angular forms the posteroventral corner of the mandible. Palatine arch. The palatine arch is deep and narrow. The palatine ventral process and the ectopterygoid form a long, slender structure, unlike the more robust form in S. vulgaris. The maxillary process of the palatine is short and straight, as in Diplodus for example. The ventral margin of the quadrate extends over the preopercular ventral limb, forming a con¯uent ridge that ¯attens posteriorly. The metapterygoid is the usual large concave bone. Opercular bones and lower part of the hyoid arch. The length of the ventral limb of the preoperculum is less than one-third of the total length of the dorsal limb and is bent through approximately 708. The width of the operculum is just over half that of the total length. The posterior margin is symmetrically concave. There are six branchiostegal rays that are acinaciform in shape.
Pectoral and pelvic girdle and ®ns. The girdles and ®ns are only partially preserved, but do not appear to differ signi®cantly when compared with other sparids. Dorsal and anal ®ns. The supraneural formula is 0=0=0 ‡ 2=1 ‡ 1: The dorsal ®n is continuous and consists of XII ‡ 11 ®n-rays. The anal ®n consists of III ‡ 9 ®n-rays. The radial of the ®rst anal ®n is thickened anteriorly, extending to a point level with the distal tip of the last haemal arch. Vertebral column and caudal skeleton. There are 24…10 ‡ 14† vertebrae. The ®rst two vertebrae are anteroposteriorly compressed, with signi®cantly shorter neural spines. The overall caudal ®n skeleton is similar to Ellaserrata as the hypural plates 1±2 and 3±4 appear to be fused (Fig. 5a). The gap between hypurals 2 and 3 is deep, extending to the urostyle. The caudal ®n is deeply forked (Fig. 5b) and hence has quite a high aspect ratio. Principal caudal ray count is 9:8. Sciaenurus Agassiz, 1845 Diagnosis. A sparid distinguished by a steeply inclined ethmoid±vomerine region and posterior ¯attening of the ethmoid crest. The elongate form of the head and partially preserved trunk suggests a body depth ratio of approximately 4:1. The lever arm of the maxilla is straight and elongate, with a reduced dorsal crest. The dorsal margin of the premaxillary alveolar process is straight. The dentition consists of a single row of caniniform teeth along the occlusal margin of the jaw.
Figure 6 Sciaenurus bowerbanki (Agassiz, 1845), BMNH P44503, Eocene, London Clay, U.K: braincase (a) dorsal view; (b) anterior view; (c) part of the lower hyoid arch in lateral view. (d) cranium and initial abdominal vertebrae in left lateral view and (e) BMNH P39441, left lateral view, with partial preservation of infraorbitals. Scale bars represent 10 mm.
EVOLUTIONARY RELATIONSHIPS OF THE SPARIDAE 343
JULIA J. DAY
Villiform teeth occur medially. The infraorbitals are heavily ornamented. Type species. Sciaenurus bowerbanki Agassiz, 1845, p. 295. Sciaenurus bowerbanki Agassiz, 1845 (Figs 6,7) 1845 1845 1854 1901 1966
Sciaenurus bowerbanki Agassiz, pp. 295±301, pl. 40. Sciaenurus crassior Agassiz, p. 307 (nomen nudum). ?Sciaenurus brevior Owen, p. 171. Sparnodus bowerbanki (Agassiz) Woodward, p. 527. Scianurus bowerbanki (Agassiz) Casier, pp. 198±211, pls 26, 27.
Holotype. BMNH P3975, dorsal surface of braincase, palatine arch, left maxilla, lower part of the hyoid arch partially preserved, opercular series, pelvic girdle, partially preserved pectoral girdle, initial vertebrae and ribs. Type locality and horizon. Lower Eocene, Ypresian, London Clay, London Basin, Sheppey (Kent), U.K. Diagnosis. As for the genus. Additional material examined. BMNH P39441, P44314, P44324, P44499, P39442, P25707, P44506, P34824, P44501, P26820, P44503. Description. Braincase. The ethmoid±vomerine region has a steep mid-dorsal crest, inclined at about 608 with respect to the parasphenoid. Posteriorly, the ethmoid crest becomes ¯attened, forming a platform that is inclined at 308 (Fig. 6a). While there is no ethmoid depression, the high angle of the crest suggests an adequate cavity to house the ascending process of the premaxilla. An anterodorsal facet on the vomer crest appears to have been caused through the articulation of the premaxillary articular process when the jaws open. The vomer is edentulous and is inclined at a shallow angle posteroventrally. The vomer posteroventral margin, lateral ethmoid posterior margin and frontal anterior margin are in the same vertical plane, indicating that the snout region is short. The ethmoid is a long, narrow bone, separating the lateral ethmoids. Posteriorly, the lateral ethmoids form a preorbital ¯ange. The preorbital ¯ange extends laterally so that it is greater than the width of the braincase at the contact of the dorsal limb of the post-temporal, but less than the width of the braincase at the contact of the ventral limb of the posttemporal. The preorbital fossa is large, similar to that of S. vulgaris. The orbitonasal canal exits anterior to the preorbital ¯ange. Posteriorly, the canal runs directly into the anterior myodome, the site for the insertion of the obliquus muscles. The frontals are inclined at approximately 208 and are separated anteromedially, forming a concave margin, similar to that found in Diplodus. The nasal posterior margin is attached to the frontal as in Dentex, rather than to both the frontal and lateral ethmoid. The posterior ¯attening of the ethmoid crest would probably have supported the nasal posteromedial surface (Fig. 6a, b). The frontal and occipital crests meet anteromedially forming a con¯uent ridge of bone. Supraorbital pores of the laterosensory system also occur in this region. In BMNH P39441 and P443324, anterior to the occipital crest, the frontals are ®nely sculptured. Posteriorly, the frontals form the anterior ¯oor and wall of the posttemporal fossae. The unroofed post-temporal fossae are large, conical cavities, extending anteriorly to a point level with the anterior insertion of the occipital crest and cover much of the otico-occipital part of the skull roof. The parietals form the central third of the frontal crest and part of the medial wall and ¯oor of the post-temporal fossae.
In BMNH P39441, the occipital crest is greater in length than height. The anterior margin is level to a point a third of the width of the orbit. Posteriorly, the occipital crest overhangs the dorsal margin of the foramen magnum. The spina occipitalis extends ventromedially between the epiotic and exoccipitals. The exoccipitals form a large proportion of the occipital area of the cranium. Dorsal to the foramen magnum, the exoccipitals are separated medially by the spina occipitalis. The foramen magnum is narrow, with height greater than width. In extant sparids these dimensions are roughly equal. The exoccipital condyles are orientated posteroventrally, and are super®cially separated medially. On the lateral surface of the condyles, directly ventral to the suture between the epiotic and exoccipital is the spinal occipital foramen. The presumed foramen for the vagus nerve lies anterodorsal to the occipital condyle and is large compared to the presumed foramen for the glossopharyngealnerve situated close to the suture between the exoccipital and prootic. Posteriorly, the basioccipital forms the occipital condyle. On the lateral face of the basioccipital is a small fossa, which probably served for the attachment of Baudelot’s ligament. In occipital aspect the braincase differs from those of extant sparids as it is deeper than wide (see Fig. 6e). The occipital fossa forms an extensive depression covering both the epiotic and exoccipital and deepening ventrally. The occipital fossa appears to be much shallower or absent in extant sparids. The epiotic forms the posterodorsal corner of the braincase, including a third of the medial wall of the post-temporal fossa and the frontal crest. A large dorsolaterally orientated fossa for the post-temporal dorsal process forms the posterior margin of the frontal crest. The pterotic forms much of the post-temporal fossa, including the posterior ¯oor and posterolateral wall. It also forms the posterior third of the pterotic crest, which is punctuated along its length by pores of the laterosensory canal. Furthermore, it forms the posterior half of the dilatator fossa including the dorsal half of the posterior facet for the hyomandibula. The small, ventrally facing intercalar extends posteroventrally as a ¯attened process for the attachment site for the m. levator operculi. Directly dorsal from this process is a fossa for the articulation of the ventral process of the post-temporal. The sphenotic forms the anterior part of the dilatator fossa and the dorsal half of the anterior hyomandibular facet. Ventrally, the sphenotic is sutured to the prootic. The origin of the m. dilatatori operculi was contained within the dilatator fossa, which extends over the posterior third of the orbit. This muscle appears not to have extended through the sphenotic via a fossa or foramen as described in some extant taxa e.g. Diplodus (Day 2002). The prootics are complex bones forming the trigeminofacialis chamber along their anterolateral margins. In BMNH P44503 the external part of this chamber, the pars jugularis, is short, as is usual in perciform ®shes (Patterson 1975). There appear to be three openings in the pars jugularis, although the central opening for the hyomandibular trunk of the facial nerve (VII) is ill-de®ned. However, observations from extant sparids show that the central opening is considerably smaller than the anterior and posterior openings. A large posteriorly orientated foramen for the internal carotid artery is situated along the contact between the prootic and the parasphenoid. The prootics also form the ventral half of the anterior articulation facet of the hyomandibula. In BMNH 44503, the process for the attachment of the m. adductor arcus palatini is not particularly well developed (Fig.
EVOLUTIONARY RELATIONSHIPS OF THE SPARIDAE
Figure 7 Sciaenurus bowerbanki (Agassiz, 1845), BMNH P44503, Eocene, London Clay, U.K: (a) camera lucida drawing of the otic-occipital part of the braincase and (b) occipital view of the braincase; Sciaenurus bowerbanki (holotype), BMNH P3975, Eocene, London Clay, U.K. Scale £1 ¢6.
7a; ap). The parasphenoid forms a ventral carina that deepens posteriorly, while the lateral margins are textured and also provide an attachment site for the m. adductor arcus palatini. The pharyngeal apophysis of the basicranium is weakly developed (Fig. 7a; pha) and is comparable in size and shape
to the apophysis in Dentex. Ventrally, the facet for the articulation with pharyngobranchial 3 of the upper pharyngeal is v-shaped. The infraorbital region. The infraorbital region is incompletely known. However, contrary to Casier (1966), both
JULIA J. DAY
infraorbitals I and II are deeper than wide, rather than only infraorbital I. This condition is regarded as unique to Sparidae (Day 2000). The ventral margin of these bones extends to the maxilla ventral margin. Infraorbital I articulates to the ventral margin of the lateral ethmoid preorbital ¯ange (Fig. 7b). The ®rst and second infraorbitals are dorsally thickened and ornamented with vertical pleats. Jaws. In all specimens examined the ascending process of the premaxilla is broken. However, as observed in extant sparids, if there is no fossa for the reception of the premaxillary ascending process, then it is probable that the ascending process was shorter than the premaxillary alveolar process. The slender alveolar process has a straight dorsal margin. The maxilla also has a straight dorsal margin and is posteroventrally expanded, extending well beyond the alveolar process. The shallow maxillary dorsolateral crest is separated from the articular condyle by a shallow palatine sulcus. The mandible is long and deep posteriorly and has a vshaped articular fossa. A short symphyseal process forms approximately a quarter of the total dentary length. The mandibular sensory canal is represented by a single row of pores. The articular descending process is broad, extending to the ventral margin of the dentary. The angular forms the posteroventral corner of the mandible. The jaw dentition consists of a single row of caniniform teeth along the occlusal margin and villiform teeth along the medial margin. It appears from the alveoli that the caniniform teeth are larger anteriorly. Hyo-palatine bones. The double-headed hyomandibula is broad and is inclined at a shallow angle anteriorly (Fig. 7a). A ridge is present extending from the anterior condyle along the hyomandibular ventral process. A large anterior ¯ange of bone anterior to the head is in contact with the metapterygoid. A foramen near the ventral end of the bone continues ventrally as a sulcus that presumably transmitted the mandibular branch of the facial nerve. On the posterodorsal margin of the hyomandibular is the short opercular process. The quadrate ventral margin overlaps the preoperculum, forming a continuous con¯uent ridge, although it is not as prominent as in the extant genus Sparus. The symplectic lies in a sulcus on the medial face of the quadrate. It is expanded posteriorly so that it overlaps the metapterygoid and preopercle. In BMNH P3975 and P39441 the ectopterygoid is bent through approximately 508, the ventral part is sutured to the quadrate anterior margin extending ventrally to the condyle (Fig. 7a). The metapterygoid is the usual large sheet of concave bone, separated from the quadrate by a fontanelle. The palatine maxillary process appears to be fairly long and is de¯ected medially. Opercular bones and lower part of the hyoid arch. The operculum anterior margin rests in a sulcus running along the length of the hyomandibular vertical process and articulates with this bone via a facet. The preoperculum is bent through 568, with the dorsal limb longer than the ventral limb. Laterally, the preoperculum ¯ange is ornamented with parallel ridges perpendicular to the posterior margin. The interoperculum and suboperculum are similar to those of other sparids. The ventral hypohyal is square-shaped in lateral view. Along the dorsolateral margin of the ceratohyal and epihyal is a sulcus for the hyoid artery. Anteriorly, the ceratohyal is bifurcated and has a well-developed dorsal process that articulates with the dorsal hypohyal. The dorsal margin is deeply concave, while the posterior margin is greatly expanded (Fig. 6c). The urohyal ventral margin forms a keel. In BMNH P44501 there are ®ve preserved branchiostegal rays. However, it would appear that the ®rst ray is missing as
indicated by a large gap between the anterior margin of the ceratohyal and the ®rst preserved ray. The head of the penultimate ray is preserved in close proximity to the interspace between the ceratohyal and the epihyal. The posteriormost ray is attached to the epihyal, while the rest is attached to the ceratohyal. The acinaciform rays are narrow and appear to be similar in size. In BMNH P44324 the basihyal is edentulous. Pectoral girdle and ®n. The post-temporal dorsal process is long and narrow compared to the ventral process and the posterior ¯ange has a smooth margin. In BMNH P3975 the long tubular dorsal process of the extrascapular extends anteromedially over the supraoccipital. The supracleithrum contacts the lateral surface of the cleithrum and is bent through approximately 328. In BMNH P34824, a large oval foramen transmitting the pterygialis nerve lies largely in the scapula although the posterior margin is formed from the corocoid. The foramen occurs in the posterior half of these bones. The coracoid appears to be as thick as the scapula along its posterior margin. It has a long anterior process and a small posterior projection. There are two postcleithra, the dorsal postcleithrum lies medial to the cleithrum. Both have wide ¯anges, unlike those of Dentex that are narrow bones. Pelvic girdle and ®n. The anterior margin of the pelvic girdle lies directly beneath the posterior margin of the braincase. The anterior subpelvic process is well developed, while the postpelvic process appear to be absent.
5. Phylogenetic analysis Of the original 87 morphological characters compiled for a data set of Recent sparids (Day 2002), 65 (70¢8%) can be scored from the most completely known fossil taxon Sciaenurus bowerbanki, while 45 (54%) characters can be scored for the least completely known Pseudosparnodus microstomus. The Eocene data set has a total of 4¢8% missing values, which is increased by 1¢5% with the inclusion of a Miocene taxon Diplodus oranensis. The addition of the fossil taxa to the Recent data set causes a substantial increase in number of missing values. Areas of the skeleton that are character rich in the extant taxa, such as the braincase, jaws and gill arches, are, with the exception of the latter character group, relatively well preserved in the fossil taxa described here. The absence of data from the gill and hyoid arches is unfortunate. All data sets analysed had signi®cant values as a result of conducting …4 (0), 1±4 (1), or 0 (2). 84. Hypurals 1 ‡ 2 and 3 ‡ 4: separate (0), fused for part of their mutual length (1) or fused (2). States 0 and 1 are more usual in sparids, however, fusion between hypurals 1±2 and 3± 4 does appear to occur in some taxa e.g. Boops and Sarpa. 85. Parahypophysis extends to hypural 1 (0), or extends to the hypural 2 ventral margin (1). 86. CINPU4 and CIHPU4 each form a double cartilage (0), a single, medium-sized oval cartilage (1), or a single, small circular cartilage (2). 87. CIHPU3 and CPHPU2 form a single cartilage with an additional separate CPHPU2 dorsally (0), a single/double CIHPU3 and double CPHPU2 (1), or a single CIHPU3 and a single CPHPU2 (2).
10. Data matrix Character number Question marks represent missing data.
yAbromasta microdon ySciaenurus bowerbanki ySparnodus vulgaris yEllaserrata monksi yPseudosparnodus microstomus yDiplodus oranensis
21111 10010 11110 10010 2111? 21311
?10?1 110?0 ?10?0 ?10?0 ?10?0 ?1??1
001?1 00000 000?1 000?0 000?1 002?1
????? 11001 ??02? ????? ????? ???2?
0111? 01110 0111? 0111? 0111? 0111?
03120 03120 03121 02120 02121 22122
0?020 0?010 0?010 0?010 0?010 1??22
0?000 00000 0?200 0?000 0?200 ??221
20000 21100 23010 21100 23100 23001
JULIA J. DAY Character number Question marks represent missing data.
yAbromasta microdon ySciaenurus bowerbanki ySparnodus vulgaris yEllaserrata monksi yPseudosparnodus microstomus yDiplodus oranensis
00??1 012?0 01200 012?0 012?1 122?1
??011 ?0011 01011 ??011 ??011 11111
2???? 212?? 2???? 1???? 2???? 2????
1???? 11??? 11??? 1???? 1???? 1????
????? ????? ????? ????? ????? ?????
????1 ????1 ????1 ????1 ????1 ????1
???01 ?1??1 ???01 ????0 ????1 ?1??1
00?2? 00??? 00?1? 00?2? 00?1? 00?1?
?? ?? ?? ?? ?? ??
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JULIA J. DAY,* Department of Biology, University College London, Gower Street, London WC1 6BT, U.K., and Department of Palaeontology, The Natural History Museum, Cromwell Road, London SW7 5BD, U.K. *Currently at the Department of Zoology, The Natural History Museum, Cromwell Road, London SW7 5BD, U.K. e-mail: [email protected]
MS received 30 August 2001. Accepted for publication 18 February 2003.