The Upper Devonian fish Bothriolepis (Placodermi: Antiarchi) from near Canowindra, New South Wales, Australia Author Johanson, Zerina text Records of the Australian Museum 1998 1998-11-25 50 3 315 348 https://journals.australian.museum/johanson-1998-rec-aust-mus-503-315348/ journal article 10.3853/j.0067-1975.50.1998.1289 ee5f89eb-2e99-4836-8a78-18f77656bc17 0067-1975 4653210 Bothrioiepis yeungae n.sp. Figs. 3-10 , lIC,J, 13-18 Bothriolepis sp. Conolly, 1965: 56 . Bothriolepis sp. Gilbert-Tomlinson, 1965: 208 . Bothriolepis sp. Long, 1982: 66 . Bothriolepis sp. Young, 1993: 251 . Bothriolepis sp. Iohanson & Ahlberg, 1997: 39 . Bothriolepis sp. Ahlberg & Iohanson, 1997: 653. Bothriolepis sp. Iohanson, 1997a: 213. Bothriolepis sp. Iohanson, 1997b: 201. Holotype . AM F101247 , external head and trunkshield, left pectoral fin in dorsal view ( Figs. 3A , lOG). Other material. AM F99692 , AM F100838-844, AM F100885-904, AM FI01232-273, 101275-277, AM F101608, AM FI01609, AM F. I02397 -399, AM F105479-540, representing internal and external views of the head and trunkshield as well as disarticulated plates. Proportions given below are taken from specimens used in PCA, including (AM Fl01247 and 105479-540). Measurements available from the author upon request. Locality and horizon. 10 km SW of Canowindra, NSW , Australia , along the road to Gooloogong ( 33°35'56"S 148°33'59" E ). The fossil fish layer is located within the Mandagery Sandstone ( Upper Devonian ) . Etymology. The species is named after Monica Yeung, Gondwana Dreaming Pty Ltd, Canberra, for her invaluable contributions to the Canowindra project. Diagnosis. Differs from all other Bothriolepis in possessing a reduced anterior process of the submarginal, separated from the posterior process of the submarginal by a wide, open notch. Characterised by: Preorbital recess trifid. Oval attachment area for prelateral on the lateral plate small, laterally oriented, separated from a strongly developed, horizontal anterior submarginal attachment on the lateral plate. Posterior submarginal attachment on lateral plate ending at posterior margin of spiracular groove. Pineal plate with reduced posterolateral corners. Postlevator cristae of anterior median dorsal plate sharply defined and short, often dissociated from the postlevator thickenings and situated in the levator fossa. Crista transversalis interna anterior on anterior ventrolateral plate obliquely oriented. Cv2 and Mml plates do not overlap on mesial margin of pectoral fin. Figure 2. A, scattergrams ofPCA axes I versus 11. B, scattergram of PCA axes I versus Ill. C, scattergram of PCA axes III versus 11. Dots indicate position of each of 77 specimens of Bothriolepis yeungae relative to these axes. Note that there is no separation of these individuals into different clusters, indicating that variation in plate measurements is not sufficient to differentiate more than one species of Bothriolepis at Canowindra . Figure 3. Bothriolepis yeungae n.sp. A, AM F.101247, holotype; E, AM F.100901; C, AM F.101271; D, AM F.101272; all dorsal view of head and trunkshield. Scale = 1 cm. Figure 4. Bothriolepis yeungae n.sp. A, AM F.100891, dorsal view of head and trunkshield; B, AM F.100901, ventral or internal view of head and trunkshield; C, AM F.101241, dorsal view of head and trunkshield; D, AM F.100891, lateral view of head and trunkshield and partial pectoral fin; E, AM F.lO1250, lateral view of head and trunkshield with proximal plates of pectoral fin. Scale = 1 cm. Figure 5. Bothriolepis yeungae n.sp. A, AM F.100802a, dorsal view of head and trunkshield; B, AM F.100802b, ventral or internal view of head and trunkshield, counterpart of Fig. SA; C, AM F.100843, closeup of internal view of headshield; D, AM F.100843, internal view of headshield and anterior portion of AMD. Scale = 1 cm . Figure 6. Bothriolepis yeungae n.sp. , smaller individuals. A, AM F.101608; B, AM F.I01243; C, AM F.101276, AM F.101277, all dorsal view of head and trunkshield; D, AM F.I01274, AM F. 101275 (PMD), internal view; E, AM F.102397; F, AM F.101240, both dorsal view of head and trunkshield, including pectoral fins (also Fig. 6A). Scale = 1 cm. Figure 7. Bothriolepis yeungae n.sp. A, AM F.100893, ventral view of external trunkshield and internal view of headshield; E, AM F.101234, internal view of headshield, partial internal view of trunkshield; C, AM F.101234, closeup of internal view of headshield; D, AM F.100842, internal view of headshield with external view of suborbitals. Scale = 1 cm . Remarks. Despite criticisms of quantitative measurements above, the diagnosis illustrates the difficulty in finding a large number of unique qualitative characters to diagnose species of Bothriolepis . However, the unusually low anterior process of the submarginal and the wide notch between this and the posterior submarginal process are present on all individuals of Bothriolepis from the Canowindra type locality. A large number of specimens of Bothriolepis are available for examination, and the majority are well preserved (although flattened) with articulated plates in the head and trunkshield. The majority of specimens are preserved in life position. Although this appears to be an ideal situation for species description and comparison, it is in fact limiting. Views of the internal surface of the head and trunkshield are present, but less common. The pectoral fin is most frequently preserved attached to the trunkshield so that the articular area on the anterior ventrolateral plate is not generally visible. Flattening of specimens means the medial wall of the pectoral fin is rarely visible, as are the plates comprising the lateral lamina of the trunkshield. These problems were also apparent in description of Remigolepis walkeri from Canowindra ( Johanson, 1997a ) .