taxonID	type	description	language	source
760A879EFF9D54650A3EFDD8FB10F9D7.taxon	description	FIG. 3 M – P, R Type locality: Rhaetian fissure fills in Carboniferous Limestone, Holwell quarry, Somerset, UK. Holotype: Specimen BATGM CD 1: anterior and mid region of the lower part of a right maxilla displaying emplacements for 24 pleurodont teeth. Diagnosis: A species of Gephyrosaurus with a similar pleurodont implantation to G. bridensis, but with significantly smaller pointed teeth. The tooth density per mm is therefore much higher than in any similar sized G. bridensis specimen. Derivation of species name: A tribute to Susan Evans, whose work has transformed our understanding of Mesozoic lepidosaurs; without her detailed account of Gephyrosaurus we would have not be able to identify this specimen. Remarks: BATGM CD 1 is a right maxilla with implantation positions for 24 teeth. Viewed medially (Fig. 3 M, O), the pleurodont implantation is clear and there are resorption pits, or gaps for shed teeth, on at least ten teeth. This high number indicates a rapid replacement of teeth, although the proportion of resorption pits is not as high as the pleurodont region of the Diphydontosaurus maxilla, BRSUG paratype 23764, or on other specimens illustrated in Whiteside (1986: pl. 1). They are within the variability of specimens of G. bridensis, however: some G. bridensis have 2 / 8 teeth with replacement pits in the anterior maxillary region, others have 5 / 8. Evans (1985) also noted variability in G. bridensis, with some Pontalun anterior maxillae specimens having low (or ‘ suppressed’) replacement, and with others (18 %) having none at all. The resorption pits are distinctive and some are relatively large (Fig. 3 O), similar to Diphydontosaurus. Only one tooth is nearly intact; the others all have missing apices. The apex of the most complete tooth (Fig. 3 P, R) is fractured, but a sharpened edge is apparent and recalls the pointed teeth of G. bridensis (Fig. 3 Q, S), rather than the slightly recurved teeth of Diphydontosaurus (Fig. 3 T). The ventral edge of the premaxillary process has a slightly downward orientation (Fig. 3 N), compared with the rest of the bone, and there is a small notch on the anterior of the process (Fig. 3 P) similar to, but larger than, a slight indentation on some specimens of G. bridensis (Fig. 3 Q). The facet for the premaxilla forms a large proportion of the pronounced premaxillary process (Fig. 3 O), as in G. bridensis. The downward orientation of the anterior lower edge of the bone is apparent when viewed medially, and is significantly more pronounced than in Diphydontosaurus and in G. bridensis (see Evans, 1980: fig. 31 B). As in G. bridensis, the anterior dental shelf is wider than that in the mid region (Fig. 3 P, Q). The other distinctive feature is the large anterior alveolar foramen (Fig. 3 N), also pronounced in Diphydontosaurus and G. bridensis, which is at the end of a series of five foramina where branches of the superior alveolar nerve exited. The number of teeth per unit length of the anterior and mid region of the maxilla, (3.5 per mm) is similar to the four of Diphydontosaurus, but is significantly higher than the 2.5 of G. bridensis. Furthermore, the minimum of 24 pleurodont teeth is a much higher number than in Diphydontosaurus (which has a total of 16 in the paratype), and sequentially they have a more consistent anteroposterior width like G. bridensis, but unlike the posteriorly increasing size found in Diphydontosaurus. The maxilla is about twice as large as the equivalent region of Diphydontosaurus, but is similar in size to G. bridensis. Other specimen referable to Gephyrosaurus: Specimen BATGM CD 2 (Fig. 3 U, V), an anterior region of the left dentary displaying emplacements for 15 pleurodont teeth ankylosed to the inside of the lateral wall, is referable to Gephyrosaurus sp. (with a close affinity to or actually G. bridensis), with nearly three pleurodont teeth per mm of the same jaw region (see Evans, 1980: fig. 42 A). That is fewer than the equivalent anterior region of the type dentary of D. avonis (approximately 4.5 per mm). The mandibular symphysis, although worn, is more similar to Gephyrosaurus than the laterally flanged feature of D. avonis (Fig. 3 B).	en	Whiteside, David I., Duffin, Christopher J. (2017): Late Triassic terrestrial microvertebrates from Charles Moore’s ‘ Microlestes’ quarry, Holwell, Somerset, UK. Zoological Journal of the Linnean Society 179 (3): 677-705, DOI: 10.1111/zoj.12458, URL: https://doi.org/10.1111/zoj.12458
760A879EFF9D54650A00FF09FDC3FE7E.taxon	materials_examined	Type species: Gephyrosaurus bridensis from early Jurassic fissure fills in Carboniferous Limestone, Pontalun quarry, South Wales, UK.	en	Whiteside, David I., Duffin, Christopher J. (2017): Late Triassic terrestrial microvertebrates from Charles Moore’s ‘ Microlestes’ quarry, Holwell, Somerset, UK. Zoological Journal of the Linnean Society 179 (3): 677-705, DOI: 10.1111/zoj.12458, URL: https://doi.org/10.1111/zoj.12458
760A879EFF9D54660842F914FEBAFE3B.taxon	diagnosis	Diagnosis: As for the type species Penegephyrosaurus curtiscoppi gen. et sp. nov. Type species by monotypy: Penegephyrosaurus curtiscoppi gen. et. sp. nov. from Rhaetian fissure fills in Carboniferous Limestone, Holwell quarry, Somerset, UK.	en	Whiteside, David I., Duffin, Christopher J. (2017): Late Triassic terrestrial microvertebrates from Charles Moore’s ‘ Microlestes’ quarry, Holwell, Somerset, UK. Zoological Journal of the Linnean Society 179 (3): 677-705, DOI: 10.1111/zoj.12458, URL: https://doi.org/10.1111/zoj.12458
760A879EFF9E54620B89FE14FC46FD69.taxon	description	FIG. 4 A – D Derivation of name: Species name from latinized Curtis and Copp, the surnames of the two researchers Mike Curtis and Charles Copp, who discovered a great deal of information on the fissure deposits of the Bristol region, and of Holwell in particular. Type locality: Rhaetian fissure fills in Carboniferous Limestone, Holwell quarry, Somerset, UK. Holotype: BATGM C 193: a part of a left dentary with emplacements for five teeth (Fig. 4 A – D). Diagnosis: A rhynchocephalian with teeth of a similar shape to those of Gephyrosaurus, but with a longer mesial – distal length of tooth. As a consequence there are at least 20 % fewer teeth in the equivalent mid-section of the dentary. There are no significant gaps on the lingual side between the bases of the posterior teeth; any space between the lower regions of the teeth is overgrown with bone. The dentition is pleuracrodont, with the teeth positioned on an obvious dental shelf. Unlike Gephyrosaurus, the teeth are permanently ankylosed distally, mesially, labially, and lingually with bone, and resorption pits are either not present or extremely rare in the posterior teeth. Remarks: BATGM C 193 (Fig. 4 A – D) is a section of a dentary broken into two parts, with a total of five teeth. The specimen is rounded at the anterior end and on the lower labial side from abrasion in transport. Despite this abrasion there are discernible tooth wear facets on the lingual side between the teeth and also on the labial side between two middle teeth (Fig. 4 A, B). These facets demonstrate that the specimen is from the dentary, and that the teeth occluded between maxillary and palatine teeth. The teeth, to some extent, resemble the simple triangular forms from the posterior acrodont region of Diphydontosaurus, but become more swollen ventrally and are more than 25 % wider mesial – distally than the largest acrodont tooth in D. avonis. The dental shelf is more clear-cut than the mere remnant in Diphydontosaurus. There are no significant gaps between the teeth bases, with the space between the two posterior teeth overgrown with bone; this compares with the noticeable space (up to 25 % of a tooth length) in the acrodont region of Diphydontosaurus (compare Fig. 4 C with E, F). The two posterior teeth are almost symmetrical, whereas the middle tooth has a steeper slope on the anterior side. The teeth are not ankylosed on the crest of the dentary and the dental shelf remains obvious, so the dentition is not truly acrodont; however, similar implanted teeth are found in juvenile Planocephalosaurus but are acrodont in adults. A similar implantation can also be found in the posterior mid-region of some Diphydontosaurus specimens, but P. curtiscoppi gen. et sp. nov. does not show alternating sized teeth, or the distal trough found in Diphydontosaurus (Fig. 4 H). The dentition is best described as pleuracrodont, as the teeth are strongly ankylosed at the lingual base as well as the mesial, distal, and labial sides. No carina is developed (Fig. 4 C, D), and the mean lateral compression (longest mesial – distal length to maximum transverse width) of the posteriormost tooth is 1.6 (Table 1), just within the range of Gephyrosaurus and below the near 1.8 found in Diphydontosaurus. Furthermore, some posterior acrodont teeth of Diphydontosaurus reach a ratio of 2.0, whereas the highest for any Penegephyrosaurus tooth is ~ 1.8. By comparison with Gephyrosaurus and Diphydontosaurus, the specimen is from the mid-posterior region of the dentary. In this respect two of the three ratios shown in Table 1 are similar to those of BRSUG 29384 from the mid region of Gephyrosaurus. The teeth are close in structure to G. bridensis, and the similarity of the upper part of the tooth shape is striking (cf. Fig. 4 A, B and I, J), particularly the change from the cusp to a lower swollen region. In the G. bridensis example from Pontalun used for comparison, the specimen comes from the mid region of the dentary above a closed Meckelian canal, and the cusps of some teeth have been worn during life so that they look as though they sit on the ‘ shoulder’ of the lower part of the tooth. The teeth bases, similar to those in G. bridensis, seem almost aligned to the jaw axis (anterior labial offset of 0 – 4 °). The dental implantation has some similarities to Gephyrosaurus, but the teeth bases, particularly of the anterior teeth, lie closer to the dental shelf and there are no discernible resorption pits (unlike some large pits present in Gephyrosaurus; Fig. 4 G), suggesting an even lower frequency (perhaps none) of tooth replacement. In the Gephyrosaurus specimens used for comparative purposes the gaps between the teeth are negligible in the posteriormost dentary dentition (Fig. 4 G), but can rise to about 10 % of the tooth length in the mid region; there are, however, gaps in Evans’ (1980) illustration of the posteriormost teeth of holotype dentary UCL T. 1503. Gephyrosaurus has mesial – distally shorter teeth and further differs in having a carina on the posterior dentary teeth (Fig. 4 G). The Penegephyrosaurus posterior teeth lingual apical – basal height to basal width mean ratio of 1.0 falls between the equivalent ratios of Diphydontosaurus (mean of 0.6) and Gephyrosaurus (mean of 1.6). Despite specimen BATGM C 193 lacking the radial ridges present on the lingual side (any present in life may have been abraded during post-mortem transport) of both Diphydontosaurus and Gephyrosaurus (Fig. 4 F, G, J) it does have characteristics in common with both genera, but shows a much greater affinity with the latter genus; however, it is over 25 % larger than Gephyrosaurus in the same jaw region, and the teeth more closely approach an acrodont condition. It is probable that like Diphydontosaurus the variation in mid-posterior dentary teeth of Gephyrosaurus is substantial, but we believe that there is sufficient difference to describe C 193 as a new genus and species. GEPHYROSAURIDAE GEN. ET SP. INDET. 1 Remarks: BATGM C 126 consists of a jaw fragment (Fig. 5 A – C), which we assign to the posterior region of a left dentary. Viewed dorsally, the bone is narrow and there is little labial expansion, which is greater in maxillae (compared with the same tooth region of the dentaries) of all species of rhynchocephalians found in the fissure deposits (e. g. compare the larger labial area in occlusal views of Fig. 5 C, D). There are discernible wear facets on both the lingual and labial sides (Fig. 5 A, B), tending to confirm the identification of the dentary; the smaller tooth base set slightly away from the lingual side than the others is also in accord with the suggestion of dentary. There are also no obvious facets for a jugal. We believe that our identification of the specimen as a dentary fragment (rather than a maxilla) is reasonable, but that the bone has clearly been worn and polished in post-mortem transport, as the fractured edge is rounded, so it is possible that other wear marks have been made indistinct. There are emplacements for four teeth (Fig. 5 C), three of which are mostly intact with bone of attachment surrounding and between the lower parts of the teeth; however, the dental shelf is obvious, particularly below the three anterior teeth emplacements, and the implantation is best described as pleuracrodont. The posteriormost tooth is more ankylosed than the others, with bone around the base in lingual and occlusal views. In occlusal view the bone around the tooth base appears similar to that of the posteriormost Diphydontosaurus dentary tooth (cf. Fig. 5 C with 4 E, F). The base of the penultimate tooth is smaller and extends less medially than its mesial neighbour (which has a broken cusp), possibly indicating a mid-dentary alternating tooth pattern like Diphydontosaurus (Fig. 4 H), or simply an erupting tooth; however, the teeth more closely resemble the simple triangular tooth shape, bearing lingual radiating ridges with a similar number of teeth per unit length, found posteriorly on Diphydontosaurus dentaries. The posteriormost tooth is much more laterally compressed (ratio of ~ 2.7; Table 1), and about 20 % longer in mesial – distal length than the posteriormost Diphydontosaurus dentary acrodont tooth. The teeth display a carina along the long axis and through the apex of the tooth, and there are wear facets that truncate the apices; these features are also seen in the Diphydontosaurus dentary tooth row (Fig. 4 E, F). Diphydontosaurus dentaries at the ‘ transition’ between the pleurodont and acrodont dentition do have a distinct shelf, but the teeth are significantly smaller than those in the posteriormost acrodont region. This specimen, albeit with a higher lingual apicobasal height to base width ratio (approximately 1.1; Table 1), is therefore similar in many respects to Diphydontosaurus; however, the gaps between the teeth are relatively smaller and do not have true acrodonty in the same region of the dentary as that genus. Also, the teeth bases seem more aligned with the jaw axis (offset by up to 6 °) compared with the anterior labial offset of about 7 – 10 ° in Diphydontosaurus (see Fig. 2 D). Therefore we cannot assign the specimen to Diphydontosaurus but realise that it has close affinities with that genus. GEPHYROSAURIDAE GEN. ET SP. INDET. 2 Remarks: Other jaw fragments include BATGM CD 7, a right maxilla with six pleurodont teeth (Fig. 5 D, E, G – I), three of which are intact on the mid and anterior sections; the anteriormost of these has a large resorption pit and there are incipient replacement pits on the other three anterior teeth (Fig. 5 E, G). This indicates frequent replacement in the anterior region. The intact teeth display simple distinctive ridges on the lingual side radiating from their apices (Fig. 5 E, G, I), and two of them have a marked trough (or groove) that runs mesial – distally across the cusp (Fig. 5 D) in this ridged region (there is also a faint trace of this trough in the anteriormost tooth). This specimen differs from Diphydontosaurus where the teeth in the equivalent maxillary region are acrodont. Moreover, the teeth of Diphydontosaurus have more complex bifurcating and sometimes trifurcating ridges just below the tooth apex (Fig. 5 J). A trough is not well developed in the maxillary teeth of that genus, or generally in Gephyrosaurus, but G. bridensis displays a slight groove on the mesial side of the cusp (Fig. 5 K); however, as the SEM image makes clear (Fig. 5 D, E), the final two teeth of the specimen appear to be more ankylosed to the dental shelf, with thick bone of attachment. There is also a significant difference from the equivalent maxillary region of Gephyrosaurus, where replacement pits are infrequent. The simple radiating ridges (Fig. 5 I) are reminiscent of similar ridges found on the lingual side of Gephyrosaurus maxillary teeth (Fig. 5 F) but the ridges can run to the base in some G. bridensis specimens, unlike in BATGM CD 7, where they appear to end mid-tooth. One interesting feature is the slightly lower base of the posteriormost teeth (Fig. 5 E, G, I), which is reminiscent but less pronounced than the more ventral position of the bases of posterior acrodont teeth found in the maxilla of Diphydontosaurus (Whiteside, 1986). Overall, there are greater affinities of the specimen to Gephyrosaurus rather than to Diphydontosaurus, but the specimen probably belongs to a new, undescribed species of rhynchocephalian. Without the current knowledge about the diversity of rhynchocephalian tooth implantation, an assignment to an early squamate would have been likely. In this respect BATGM CD 7 is similar to a fragment of a maxilla with pleurodont teeth bearing radially ridged cusps or ‘ striae’ from the early – mid Jurassic of India, attributed to Squamata by Evans, Prasad & Manhas (2002: fig. 9 C). Pleurodonty alone is equivocal evidence as it is found in rhynchocephalians, and therefore without any additional evidence of the presence of squamates, and considering the radial ridges in G. bridensis (Fig. 5 F), we attribute the specimen to an indeterminate gephyrosaurid. LEPIDOSAURIA? GEN. ET SP. INDET Remarks: BATGM CD 9 (Fig. 5 L, M) consists of a small, worn, jaw fragment with two robust triangular teeth that are damaged on the lingual side. We tentatively identify the fragment as the posterior part of a dentary, as the largest tooth appears to be at the rear terminal end of the dental row. The teeth fuse anteriorly, and are reminiscent of, and are of similar anteroposterior width, some damaged specimens of Clevosaurus at Tytherington. However, the dentition appears to be pleuracrodont (rather than acrodont) with the teeth firmly ankylosed to the labial wall but sitting much lower on the dental shelf of the lingual side. It does not appear that the teeth are ankylosed in a socket, so that it is unlikely that the specimen has procolophonid affinities. There is insufficient detail in the specimen to make a confirmed assignment except to reptilia in general, and most probably to Lepidosauria.	en	Whiteside, David I., Duffin, Christopher J. (2017): Late Triassic terrestrial microvertebrates from Charles Moore’s ‘ Microlestes’ quarry, Holwell, Somerset, UK. Zoological Journal of the Linnean Society 179 (3): 677-705, DOI: 10.1111/zoj.12458, URL: https://doi.org/10.1111/zoj.12458
760A879EFF84547E0858FD01FE5FFB9B.taxon	description	FIG. 7 A – C Referred material: Specimen BATGM CD 4, an anterior mid-region fragment of a left dentary from Holwell ‘ Microlestes ’ quarry, Somerset, UK (Fig. 7 A – C). Remarks: BATGM CD 4 is a left dentary with a different tooth implantation than is found in the other jaws. There is a clear Meckelian canal (Fig. 7 A), and on the labial side a foramen has a deep groove that is directed posteriorly (Fig. 7 B). The dentition is ankylothecodont, with the base of the teeth ankylosed on the dental shelf rather than to a labial wall, and with the base of the tooth lying below the surface of the bone. From the broken tooth it is clear that they sit and are ankylosed in shallow alveoli (Fig. 7 C). One tooth, identified as emergent because it is significantly below the estimated full heights of the teeth on either side, has a tricuspid apex, but the others are too damaged to describe any details of cusps. The emerging tooth has a wear facet on the central cusp and there is ankylosing bone formed around the base on the labial side. The two teeth behind the tricuspid are larger, and these three teeth have a slightly more ovoid base, wider transversely than anteroposteriorly, compared with the more anterior first tooth that is subconical. Also, the teeth bases form a pattern with the two larger posterior teeth lying almost the entire width across the jaw, with their medial side near to or at the lingual margin; the two anterior teeth are emplaced more mid-dentary, and the medial bases do not come as close to the lingual edge. This specimen is clearly referable to V. inopinatus, and from the description of the paratype NMHUK PV R 36849 by Robinson (1957 b), we can judge that it is from the anterior mid-region behind the symphysis roughly in tooth positions 5 – 8. The anteroposterior lengths of the tooth bases fit the pattern of size in the paratype, with the smallest tooth in the sixth position between a larger anterior tooth and posteriorly the largest teeth. The fully erupted teeth are in the same size range (~ 0.4 – 0.6 mm) as found in the paratype. The emerging tooth conforms to Robinson’s view that tooth replacement was frequent in this species, and the wear on the middle cusp of the tricuspid (Fig. 7 C) also accords with the paratype (Robinson, 1957 b: table, p. 284).	en	Whiteside, David I., Duffin, Christopher J. (2017): Late Triassic terrestrial microvertebrates from Charles Moore’s ‘ Microlestes’ quarry, Holwell, Somerset, UK. Zoological Journal of the Linnean Society 179 (3): 677-705, DOI: 10.1111/zoj.12458, URL: https://doi.org/10.1111/zoj.12458
760A879EFF84547E0858FD01FE5FFB9B.taxon	discussion	Remarks: BATGM CD 8 is a jaw fragment with four robust teeth (Fig. 7 D – F). The dental implantation is acrodont but the teeth are more columnar than the triangular shape of the sphenodontians, such as Clevosaurus and Diphydontosaurus. There are no ridges characteristic of Planocephalosaurus, and there is a lack of wear on the jaws from occlusion found in the sphenodontians. Rather, it is the type of acrodonty described for the procolophonid Soturnia by Cabreira & Cisneros (2009). One of the teeth has a wear facet on the labial side, and from this and the Meckelian groove we have identified the specimen as the anterior of a right dentary. There are no distinguishing apomorphies that can assign this specimen to a specific genus.	en	Whiteside, David I., Duffin, Christopher J. (2017): Late Triassic terrestrial microvertebrates from Charles Moore’s ‘ Microlestes’ quarry, Holwell, Somerset, UK. Zoological Journal of the Linnean Society 179 (3): 677-705, DOI: 10.1111/zoj.12458, URL: https://doi.org/10.1111/zoj.12458
760A879EFF86547F0A0FFBB4FE00FC8E.taxon	discussion	Remarks: The small jaw fragment BATGM CD 62 (Fig. 7 G, H), with two near-overlapping teeth, derives from a different taxon. It is unclear where in the jaw the specimen is located, but a dentary fragment is most likely as there is some wear on both lingual and labial sides. The teeth are distinctively truncated and have a basin, developed lingually, particularly in one tooth. It is unclear where the affinities of this specimen lie; it may be sphenodontian but the most similar tooth form occurs in the anterior dentary dentition of the enigmatic Xenodiphyodon petraios Sues & Olsen, 1993. Sues & Olsen (1993) were unsure of the affinities of Xenodiphyodon, suggesting that it may be related to trilophosaurs such as Variodens or procolophonids. The tooth implantation of BATGM CD 62 is quite different from our Variodens specimen (BATGM CD 4), and may be of an unusual acrodont implantation; however, there is a shallow sulcus at the base of the shorter? posterior tooth, indicating that the tooth may lie in a socket. It is therefore possibly ankylothecodont, suggesting procolophonid affinities. REPTILIA INDET Remarks: BATGM CD 63 (Fig. 7 I, J) is an isolated, probable archosauromorph, tooth nearly 3 mm long with an apparently non-serrated carina on one side. The specimen is worn but has a blunt apex. The tooth does not readily fit the 16 morphotypes of Heckert (2004), or those from phytosaurs, and its affinities are unclear. BATGM C 24, an ungual phalanx (Fig. 7 K, L), is difficult to assign, but the size and general shape suggests that it might be from a burrowing animal, as the morphology is reminiscent of the third digit ungual of the manus of extant fossorial golden moles. It may belong to a procolophonid. Procolophonids probably used their claws for digging, with the two innermost digits of the manus being the most robust (Colbert & Kitching, 1975).	en	Whiteside, David I., Duffin, Christopher J. (2017): Late Triassic terrestrial microvertebrates from Charles Moore’s ‘ Microlestes’ quarry, Holwell, Somerset, UK. Zoological Journal of the Linnean Society 179 (3): 677-705, DOI: 10.1111/zoj.12458, URL: https://doi.org/10.1111/zoj.12458
760A879EFF86547F0A0FFBB4FE00FC8E.taxon	discussion	Remarks: Premaxillae: This is the first record of bony fish that can be found in non-marine environments to be reported from Holwell. BATGM 42 f (Fig. 8 A, B) is a worn premaxilla that has the shape of an elongate triangle, measuring 2.18 mm long and 1 mm high at the deepest point (at the short ascending process). The posterior margin is inclined and the whole element is slightly bowed longitudinally. The ventral or oral margin is narrow and marked by eight tooth bases; no complete teeth are present. The external surface of the element is not ornamented, with the original ganoin covering having been removed by post-mortem wear during bone transport, and shows evidence of a shelf of bone along the upper external margin. A second premaxilla in the collection (BATGM 42 h; Fig. 8 C, D), perhaps also belonging to a pholidophorid, is rather deeper and has ten tooth bases along the oral margin.	en	Whiteside, David I., Duffin, Christopher J. (2017): Late Triassic terrestrial microvertebrates from Charles Moore’s ‘ Microlestes’ quarry, Holwell, Somerset, UK. Zoological Journal of the Linnean Society 179 (3): 677-705, DOI: 10.1111/zoj.12458, URL: https://doi.org/10.1111/zoj.12458
