Pseudopus laurillardi (Lartet, 1851)

Ivanov, Martin, Čerňanský, Andrej, Bonilla-Salomón, Isaac & Luján, Àngel Hernández, 2020, Early Miocene squamate assemblage from the Mokrá-Western Quarry (Czech Republic) and its palaeobiogeographical and palaeoenvironmental implications, Geodiversitas 42 (20), pp. 343-376 : 350-351

publication ID	https://doi.org/ 10.5252/geodiversitas2020v42a20
publication LSID	urn:lsid:zoobank.org:pub:8FF2A078-CE45-4BF1-A681-00136F57375E
DOI	https://doi.org/10.5281/zenodo.4488219
persistent identifier	https://treatment.plazi.org/id/03C587C7-430D-FFEF-FC16-FE2A4A12FC1D
treatment provided by	Felipe
scientific name	Pseudopus laurillardi (Lartet, 1851)
status

Treatment

( Fig. 5 View FIG A-D)

Pseudopus sp. – Ivanov et al. 2006: 229, table 2 (in part).

MATERIAL. — MWQ, early Miocene, Burdigalian, Orleanian, MN 4: 1/2001 Turtle Joint: parietal (Pal. 1402). 2/2003 Reptile Joint: parietal (Pal. 1574 ).

DESCRIPTION Parietal Two parietals are partially preserved. The specimen Pal. 1574 represents the posterior region of the parietal table, together with the base of the right supratemporal process, whereas only the central portion of the right side of the parietal is preserved in the second specimen (Pal. 1402). The anterior region of the preserved portion of the parietal table is completely covered by osteodermal shields fused to the bone. These shields bear ornamentation which consists of pits, small ridges and short grooves. The small occipital shield, located in the posterior mid-region, is trapezoidal in shape. Its anteroposteriorlength is less than that of the posteriorly located smooth area (area levis) in both specimens. However, the smooth area is large only in specimen Pal. 1574. The interparietal shield, located anterior to the occipital shield, is only hardly distinguished from the large parietal shields located laterally. There is no parietal foramen within the preserved portion of the bone. The base of the supratemporal process is broad. Here, the arcuate edge (carina arcuata; sensu Klembara et al. 2017a) is developed. The supratemporal process gradually widens distally (this can be observed especially in specimen Pal. 1402). On the internal side, the process bears a robust ventrolateral ridge. In the larger specimen, Pal. 1574, a free ventrolateral surface is present lateral to the ridge. This is absent in the smaller Pal. 1402. In this specimen, a longitudinal facet for the supratemporal can be observed on the posterolateral side of the ridge. This facet reaches approximately to the level of the posterior margin of the parietal table. On the internal side of specimen Pal. 1574, a large oval parietal fossa is located in the posterior mid-region. It is bordered ventrally by the parietal lamina. Posterior to the parietal fossa, a postfoveal crest (crista postfovealis) is located. Between the postfoveal crests and the posterior margin of the parietal table, a shal - low parietal notch is present. The cranial parietal ridges (cristae cranii parietalis) are partly preserved, the right one can be observed in the specimen Pal. 1402. Lateral to the cranial ridge, muscular facies are well developed, forming the lateral border of the parietal.

REMARKS

The presence of muscular facies (see Klembara et al. 2017a) on both parietals and the presence of the postfoveal crest allow the allocation of this material to Pseudopus (although it should be noted that short postfoveal crests are also present in Ophisaurus holeci [ Klembara 2012; Čerňanský & Klem- bara 2017] and in some cases, narrow muscular facies can be observed in very large adult individuals of this taxon as well [see Klembara et al. 2017b]). Three species of Pseudopus are documented from early Miocene deposits of Europe: P. laurillardi , P. ahnikoviensis and P. confertus (see Klembara et al. 2010; Klembara 2012; Klembara 2015 – P. rugosus was later renamed to P. confertus by Klembara & Rummel 2018). The parietal Pal. 1574 clearly exhibits features present in P. laurillardi : 1) the presence of free ventrolateral surface (facies ventrolateralis sensu Klembara et al. 2010) of the supratemporal process, located lateral to the ventrolateral ridge (this feature is absent in P. ahnikoviensis , see Klembara 2012); and 2) the type of sculpture present on osteodermal shields fused to the bone, consisting of pits, small ridges and grooves rather than being vermicular as it is in P. ahnikoviensis (see Klembara 2012). Another feature is the absence of the parietal foramen in the preserved portion of the parietal – in P.confertus , this foramen is located closer to the posterior margin of the floor of the parietal fossa (seeKlembara 2015). We can therefore estimate that the parietal foramen in Pal. 1574 was located more anteriorly than it is in P. confertus . The second parietal, specimen Pal. 1402, is problematic. The free ventrolateral surface of the supratemporal process appears to be absent. However, if size is considered, this specimen represents a small individual. In the small parietal described by Klembara et al. (2010: p. 166, fig. 5B), this feature is only incipiently developed and thus can be influenced by ontogeny. If our allocation is correct, then the parietal Pal. 1402 represents a juvenile individual of P.laurillardi (this can be supported by the presence of a similar type of ornamentation to that in Pal. 1574).