Ophisaurus sp.
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publication ID |
https://doi.org/10.3897/fr.28.175508 |
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publication LSID |
lsid:zoobank.org:pub:EB892979-42F4-49F2-85B3-EB471A9E327B |
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DOI |
https://doi.org/10.5281/zenodo.17781534 |
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persistent identifier |
https://treatment.plazi.org/id/E1AA9746-B5DF-5FB4-B83E-8C07F96DCD7C |
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treatment provided by |
by Pensoft |
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scientific name |
Ophisaurus sp. |
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Ophisaurus sp. sensu lato
Fig. 3 M View Figure 3
Material.
One parietal ( IPS-PAM 207-29 ).
Description.
Parietal. The fossil corresponds to the posterior right part of the parietal table ( lamina parietalis). The supratemporal processes are broken, but the right one, which preserves its anteriormost portion, appears to have diverged posteriorly. In dorsal view (Fig. 3 M 1 View Figure 3 ), a well-developed dermal ornamentation is present on the dorsal surface of the parietal table, and the frontoparietal, interparietal, lateral, and occipital shields are clearly recognizable. Laterally, the limits of this ornamented surface appear to contact the lateral margins of the bone, while posteriorly it does not reach the posterior margin of the parietal table due to the presence of a large, smooth area ( area levis). The ornamentation consists of isolated pits, sometimes located in deep grooves and weak ridges, with a convex posterior limit ending near the arcuate edge. Posteriorly, the arcuate carina is rounded and likely extended on each side along the parotid process. A wide, elliptical pineal foramen is present in the middle of the table. Based on the position of the foramen relative to the posterior margin of the parietal, the fossil does not appear to have been particularly elongated, although this is probably because it represents a juvenile. In ventral view (Fig. 3 M 2 View Figure 3 ), the ventral crests are visible on the smooth ventral surface. The anterolateral and posterolateral crests contact each other, as do the anterolateral and medial crests. The contact of the anterolateral ventral crest with the medial ventral crest typically splits the margin of the parietal fossa into two sections, referred to as the crista juxtafovealis (anterior to the contact) and crista postfovealis (posterior to the contact) following Klembara et al. (2010). However, due to breakage, the postfoveal crest is not visible in this fossil. The parietal fossa appears to be inverted V-shaped, narrow, and deep, and is cut off at mid-length by the arched carina. No parietal notch is visible posteriorly, and the posterior portion of the wide parietal fossa is observable in ventral view.
Remarks.
The clade Anguinae currently comprises three extant genera: Anguis (Europe and Western Asia), Ophisaurus (sensu Klembara et al. 2014; i. e., including Dopasia and Hyalosaurus from North America, Northern Africa, and Southeast Asia), and Pseudopus (southeastern Europe to Central Asia). There is abundant fossil data on this clade in Europe from the Eocene to the Early Pleistocene (see Loréal 2025, for a recent update). However, fossil data from North Africa are much rarer. Anguid lizards ( Anguidae indet.) are known from the Middle Miocene of Beni Mellal ( Morocco; Rage 1976) and the Late Miocene (Vallesian) of Asif Assermo ( Morocco; in Stoetzel 2009). Ophisaurus s. l. has been reported from the early Late Miocene (Vallesian) of Oued Zra ( Morocco; in Stoetzel 2009). Ophisaurus sp. has been reported from the Late Miocene of Guefaït 1 A ( Blain et al. 2013), and cf. Ophisaurus from the Late Pliocene – Early Pleistocene of Guefaït 2 and 4 (unpublished observations) and from the Pleistocene of Irhoud Ocre ( Morocco) (in Stoetzel 2009). At least the extant Moroccan species O. koellikeri has been documented at the Plio-Pleistocene transition of Ahl al Oughlam ( Morocco; Bailon 2000) and in the Holocene layers of El Harhoura 2 ( Morocco; Stoetzel et al. 2008). The anguid lizards from the Middle Miocene of Beni Mellal have not been illustrated, but according to Rage (1976) they differ from Ophisaurus .
The fragmentary fossil parietal from PAM 207 differs from the genera Pseudopus and Smithosaurus by the apparent absence of the facies muscularis (muscular surface), which is well developed in extant and fossil Pseudopus ( Klembara 1979) and in the extinct Smithosaurus (Early Miocene of Germany; Vasilyan et al. 2022). In addition, the occipital shield is usually much more developed in Pseudopus than in the fossil. In Anguis , the cranial parietal crest is usually better developed, especially at its junction with the ventrolateral ridge; the anterior end of the ventrolateral ridge of the supratemporal process is located more anteriorly on the bone; and the smooth area ( area levis) is relatively reduced. According to Klembara (2012), Klembara et al. (2017), and Klembara and Rummel (2018), the area levis is shorter than the occipital shield in Anguis , whereas it is as long as the shield in Pseudopus and Ophisaurus . However, Villa and Delfino (2009) suggest a certain degree of variation in this feature. The absence of a parietal notch may be another character distinguishing the fossil from Anguis gr. An. fragilis ; however, according to Villa and Delfino (2019), the development of the parietal notch undergoes ontogenetic variation in this taxon, with its depth increasing during growth.
Attribution to Ophisaurus sensu lato relies on the posterior position of the parietal fossa, which is deep and cut at mid-length by the arcuate carina. Comparison among the different species of the genus is hampered by the fragmentary state of the fossil, as well as by the possibility that it represents a juvenile individual.
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