Protobothrops sp.

Lin, Chien-Hsiang, Lin, Si-Min, Chien, Chi-Wei, Lin, Te-En, Nazir, Haroon & Singh, Ningthoujam Premjit, 2025, First fossil frog and snake assemblage from southern Taiwan: a window into Pleistocene herpetofauna and palaeoenvironments in subtropical East Asia, Fossil Record 28 (2), pp. 293-308 : 293-308

publication ID

https://doi.org/10.3897/fr.28.164568

publication LSID

lsid:zoobank.org:pub:CD488CEE-E71A-4875-AE67-BECB421A0661

DOI

https://doi.org/10.5281/zenodo.17237095

persistent identifier

https://treatment.plazi.org/id/30D1BFF8-FD18-54F9-B7F7-B999D17EFFB2

treatment provided by

by Pensoft

scientific name

Protobothrops sp.
status

 

Protobothrops sp.

Fig. 7 A View Figure 7

Material.

One vertebra ( ASIZF 0101053 ).

Description.

In anterior view, the cotyle is large and circular. The prezygapophyses are dorsally inclined though their prezygapophyseal processes are not preserved. The zygosphene roof is slightly convex, with articular facets inclined dorsally. Paired, deeply set large paracotylar foramina are present on both sides of the cotyle. The parapophyseal processes are broken, but they extended beyond the cotyle.

In posterior view, the neural arch is extremely depressed (vaulting ratio = 0.19). The zygantrum is mediolaterally wide and deep. The condyle is rounded and relatively narrowerthan the neural canal.

In dorsal view, the anterior margin of the zygosphene is straight, with two pointed lateral lobes. Prezygapophyseal articular facets are oval. A deep posterodorsal notch exposes a large portion of the condyle. The neural spine extends longitudinally along the dorsal surface of the neural arch and terminates posterior to the posterior medial notch.

In ventral view, the centrum is triangular. Subcentral foramina are deep and restricted to the anterior part of the centrum. Parapophyses and diapophyses are distinctly observed. The parapophyseal processes project anterolaterally. Postzygapophyseal articular facetsare oval. Subcentral grooves and ridges are distinct.

In lateral view, the neural spine is broken ventrodorsally. The zygosphene articular facets are elliptical. The lateral foramina are deep and situated in the middle part of vertebra. The interzygapophyseal and subcentral ridges run straight anteroposteriorly. The hypophysis originates at the middle part of the centrum and extends beyond the level of the condyle.

Remarks.

The presence of well-developed hypapophysisacross the trunk column in Asian colubriformsindicates potential affinity with Elapidae , Viperidae , Homalopsidae , or Natricidae (originally considered as Natricinae ; Szyndlar 1984, 1991 b), as this character is considered apomorphic ( Zaher 1999). Among these families, the referred specimen resembles more to the family Viperidae , particularly due to the following combination of features: presence of hypapophysis, depressed neural arch, dorsally inclined prezygapophyses and anterolaterally directed parapophyseal processes ( Szyndlar and Rage 1999, 2002; Zaher 1999; Zaher et al. 2009, 2019).

Viperidae includes three monophyletic subfamilies: Viperinae (or “ true vipers ”), Azemiopinae , and Crotalinae (or “ pitvipers ”), with the latter two forming a sister clade to Viperinae ( Wüster et al. 2008; Alencar et al. 2016). This vertebra can be confidently classified within Crotalinae due to its short and wide vertebra, thick hypapophysis that originates near the middle of the centrum, and large cotyle and condyle ( Holman 2000), although these can also be found in some large viperines. Furthermore, the fossil vertebra most closely resembles Protobothrops or Trimeresurus rather than Gloydius , based on its undeveloped prezygapophyseal accessory processes, straight zygosphenal margin in the dorsal view; rounded shape cotyle and condyle, and straight subcentral ridge in the lateral view ( Ikeda 2007). Among extant taxa, Trimeresurus stejnegeri — a small and common pitviper in Taiwan — is a possible comparison. However, the fossil vertebra is significantly larger than that of a large adult T. stejnegeri (Fig. 7 C View Figure 7 ), suggesting that the specimen more likely represents a larger crotaline Protobothrops .

Within Protobothrops , the fossil is most comparable to P. mucrosquamatus , the only extant species of this genus occurring in Taiwan. However, the prezygapophyseal accessory processes in the fossil are more pointed and anteriorly directed, whereas in P. mucrosquamatus , the same processes are broader and more laterally expanded (Fig. 7 B View Figure 7 ). Therefore, we conservatively retain the identification at the genus level.

Alethinophidia indet.

Fig. 8 View Figure 8

Materials. Six trunk vertebrae ( ASIZF 0101054 –1059).

Description. All the specimens referred here are fragmentary, but they share a few common characteristics such as the absence of hypapophyses, rounded cotyles and condyles, a large neural canal, a dorsally convex zygosphene, and distinct subcentral ridges and grooves. Prezygapophyses are preserved in a few specimens (e. g., Fig. 8 A View Figure 8 ), displaying oval shape that extend laterally.

In specimens ASIZF 0101058 and 1059 (Fig. 8 E, F View Figure 8 ), endozygantral foramina can be observed within the zygantrum. In ventral view, the haemal keel is well-developed, oblanceolate in shape, and subcentral foramina are observable in specimens ASIZF 0101055 , 1056, and 1058 (Fig. 8 B, C, E View Figure 8 ). The neural spine is damaged anteroposteriorly in all specimens. In lateral view, the interzygapophyseal and subcentral ridges are straight, and lateral foramina are present.

Remarks. The absence of hypapophysis indicates that these are mid- or posterior trunk vertebrae. However, due to the fragmentary nature of the specimens and the lack of genus-level diagnostic characters, more precise identification is not possible. However, based on the preserved features, all specimens can be attributed to Alethinophidia indet.

Kingdom

Animalia

Phylum

Chordata

Class

Squamata

InfraOrder

Caenophidia

Family

Viperidae

SubFamily

Crotalinae

Genus

Protobothrops