Genibatrachus baoshanensis, Gao & Chen, 2017

Gao, Ke-Qin & Chen, Jianye, 2017, A New Crown-Group Frog (Amphibia: Anura) from the Early Cretaceous of Northeastern Inner Mongolia, China, American Museum Novitates 2017 (3876), pp. 1-40 : 4-5

Genibatrachus baoshanensis , sp. nov.

Figures 2–6

ETYMOLOGY: The species epithet refers to the Baoshan township near the type locality .

HOLOTYPE: PKUP V0401 , an incomplete adult skeleton preserved in volcanic shales, exposed in part-and-counterpart slabs.

REFERRED SPECIMENS: PKUP V0402–V0412; all specimens are preserved in volcanic shales, exposed in part-and-counterpart slabs. PKUP V0410–V0412 are juvenile individuals based on their smaller body size, whereas the remaining specimens are adults.

TYPE LOCALITY AND HORIZON: Pigeon Hill (N48°66′43.38″/E123°87′28.85″), near Taipingqiao village, approximately 18 km northwest of Baoshan township, Morin Dawa Daur Autonomous Banner, Hulunbuir, Inner Mongolia, China; Lower Cretaceous Guanghua (= upper part of Longjiang) Formation (?Barremian-Aptian).

DIAGNOSIS: A new fossil belonging to the Pipanura (a clade consisting of the Pipoidea, Pelobatoidea, and Neobatrachia) based on the combination of the following characters: palatine present; eight presacral vertebrae; centrum procoelous; separate ribs present on the presacral II–IV; ribs V–VIII fused to the transverse processes of the presacral. It is distinguished from all other taxa within the Pipanura with the combination of the following characters: alary process of premaxilla bifurcated; nonimbricate presacral neural arches; transverse processes of presacral V–VIII laterally oriented; unexpanded sacral diapophysis.

Figures

FIGURE 2. Photograph of the holotype of Genibatrachus baoshanensis, gen. et sp. nov. (PKUP V0401): incomplete skeleton exposed on part-and-counterpart shale slabs. A, skull and postcranial skeleton exposed in dorsal view; B, impressions of the skull and postcranial skeleton exposed in counterpart slab of A.

FIGURE 3. Holotype of Genibatrachus baoshanensis, gen. et sp. nov. (PKUP V0401): line drawing of the incomplete skeleton and impressions of the skeleton in dorsal view, as exposed on part-and-counterpart shale slabs.

FIGURE 4. Referred specimens of Genibatrachus baoshanensis, gen. et sp. nov. (juvenile individuals): A, PKUP V0411 in dorsal view; B, PKUP V0412 in ventral view.

FIGURE 5. Palatal structures of Genibatrachus baoshanensis, gen. et sp. nov. (PKUP V0412). Arrow points to the ossified posteromedial process of the hyoid.

FIGURE 6. Ontogenetic fusion of ribs to transverse process of the vertebra: A, PKUP V0410 (juvenile); B, PKUP V0411 (juvenile); C, PKUP V0406 (young adult); D, PKUP V0404 (fully grown adult). Scale bars = 5 mm. Note that PKUP V0410 and V0411 show all trunk vertebrae with free ribs articulated with the transverse process, PKUP V0406 shows a transitional stage of fusion of the ribs on posterior trunk vertebrae, whereas PKUP V0404 shows fully fused ribs to the transverse process on the posterior trunk vertebrae.