【摘要】 本文记述了产自山东临朐中中新统的大锄足蟾—新种 Macropelobates cratus sp. nov.,讨论了亚洲化石锄足蟾类与欧美相关类群的关系.此外,根据对化石的详细研究和对比,本文重新厘定了临朐蟾蜍 (Bufo linquensis, Young 1977) 的含义,对其原始描述作了补充和修订.更多还原

【Abstract】 In the present paper, Macropelobates cratus, a new fossil spadefoot toad collected from Shanwang (middle Miocene) of Linqu County, Shandong Province in 1977, is described and a revision of Bufo linquensis (C. C. Young, 1977) is made based on the re-examination of the fossil specimens. The original paratype of Bufo linquensis is revised as a pelobatid form, which can be Changed into the name of Macropetobates cratus. I. Fossil Description Order Salientia Noble 1931 Suborder Anomocoela Noble 1931 Family Pelobatidae Lataste 1876 Genus Macropelobates Noble 1924 Macropelobates cratus sp. nov. (Text-fig. 1; Pl. I) Holotype A nearly complete specimen split into two valves, both bear bones and prints of the skeleton. IVPP no. V 7700. Locality and Horizon Linqu, Shandong; Shanwang Formation (SW 2, MN5). Diagnosis Size large. Skull greatly wider than long, with bony sculpture developed on dorsal surface. Maxillary teeth well developed, vomer teeth reduced, and palatine present. Presacral vertebrae eight, in procoelous form. Sacral wing strongly broadened in fan shape. Urostyle somewhat stocky and articulates with sacral vertebra in monocondylar way. Pelvic girdle long, no ilial crest. Leg short and massive, femur slightly longer than tibiofibula. Prehallux much developed and specialized into foot spade. Remarks The following characteristics lead us to include V 7700 specimen into Pelobatidae: skull strongly ossified with dermal sculpture developed on bones of nasal, frontoparietal, squmasal and maxilla; maxilla bears fine and close ranged teeth. Diapophyses of 5th through 8th vertebrae strongly slant forward. Sacral wing strongly expanded. Pectoral girdle in arciferal type. Prehallux spcialized into foot spade. By comparison with the Tertiary fossil pelobatids of the world, our specimen shows the morphological characteristics quite different from the forms such as Eopelobates, Scaphiopus etc. The closest one is the Macropelobates osborni diseovered from the Oligocene of Mongolia (Noble, 1924). Yet there exist certain basic differences between M. osborni and V 7700. The latter is longer in pelvic girdle, strikingly larger in body size and later in geological time than the former. Therefore, our specimen is here identified as a new species of the genus Macropelobates. II. On the Restudy of Bufo iinquensis Bufo linquensis was named by Professor C. C. Young in 1977. All the specimens including type and paratype tare housed in the Museum of Shandong Province. According to the re-examination of the specimens by the author, the original description of the type specimen is completed and demended, and the specimen originally described as the paratype of Bufo linquensis is allocated to Pelobatidae in this paper. 1. The emending of Bufo linquensis Suborder Proeoela Noble 1931 Family Bufonidae Gunther 1958 Genus Bufo Laurenti 1768 Species Bufo linquensis Young 1977, emend. nov. excl. spec. H11-O39 (Young’s paratype) (Text-fig. 2; Pl. II, A) Emended Diagnosis Size large. Head striking wider than long; snout wide and rounded; no maxillary teeth and no vomer teeth developed. Parasphenoid blade shorter than its half width across alae; alae well developed and perpendicular to blade. Presacral vertebrae eight, in procoelous form; diapophyses massive and much developed. Urostyle articulates with sacral by double condyles. Sacral diapophysis strongly expanded. Pectoral girdle in arciferal type. Pelvic girdle in U shape, no?ilial crest present. Leg short, tibiofibula shorter than femur. Remarks From all the above characteristics shhown on H11-O38, it is evident that Professor C. C. Young was certainly right in including the specimen into genus Bufo as a new species in 1977. By comparison, Bufo linquensis appears more closely related to Bufo gargarizans than the other species of Bufo; howver, these two species differ very strikingly from each other in body size, parasphenoid shape, massive devotee of diapophyses and in different geological time. Therefore, there is no doubt that Bufo linquensis is a rightfully erected species of bufonids. 2. The revising of specimen H11-O39 As the result of re-examination and remeasurement, the morphological characteris- tics showing on specimen H11-O39 (Pl. II, B) can be listed as follows: 1) Size very large and bones fairly massive 2) Head broad, with well-developed dermal sculpture on dorsal suriface of skull 3) Fine teeth developed on maxilla 4) Palatine present and fairly massive 5) Pectoral girdle in arciferal type 6) Presacral vertebrae eight, in procoelous form 7) Diapophyses of 5th throgh 8th vertebrae strikingly slant farward 8) Sacral wing strongly broadened in fan shape 9) Urostyle articulates with sacral by single condyle 10) Prehallux much developed and specialized into foot spade In view of the characteristics described above, it is beyond any doubt that the specimen H11-O39 represents a fossil form,belonging to pelobatids rather than bufonids. Its body length is up to 167 mm, no any Asian bufonid form could reach such a large size as so far known. The measurements of this specimen are very close to that of Macropelobates cratus described above in the present paper and these two specimens were diseovered from the same locality and the same horizon of Linqu, Shandong. Therefore, the cpecimen H11-O39, the original paratype of Bufo linquensis described by Professor C. C. Young in 1977, should be allocated to Pelobatidae as the paratype of Macropelobates cratus.更多还原