COLUBRIDAE Oppel, 1811

Delfino, Massimo, Bailon, Salvador & Pitruzzella, Gaetano, 2011, The Late Pliocene amphibians and reptiles from “ Capo Mannu D 1 Local Fauna ” (Mandriola, Sardinia, Italy), Geodiversitas 33 (2), pp. 357-382 : 374-375

Family COLUBRIDAE Oppel, 1811

“Colubrine” type (trunk vertebrae without hypapophysis) ( Fig. 7 A-D)

MATERIAL EXAMINED. — Maxilla: 1 fragment; trunk vertebra: 21.

DESCRIPTION

The fragmentary right maxilla is represented by a posterior section of this element extending from an undetermined point following the prefrontal process (not preserved) and the tooth position following the ectopterygoid process (preserved); the ectopterygoid process corresponds to two tooth sockets, hosting the only preserved tooth, and part of the preceding socket; two more tooth sockets are placed anteriorly to the ectopterygoid process; the toothed region is preceded by a long diastema corresponding to at least two tooth positions; in ventrolateral view, an evident change of slope corresponds to the boundary between the diastema and the toothed region.

The most common vertebral morphotype is characterized by an elongated centrum (whose length can reach 2.4 mm); subcircular cotyles and condyles; parapophysis and diapophysis separated by a shallow depression; parapophysis anteroposteriorly longer than diapophysis; parapophyseal processes absent; haemal keel well defined and usually modestly widened posteriorly; pre- and postzygapophyses weakly tilted dorsally; prezygapophyseal processes slender, pointed and long up to half the width of the prezygapophyseal facet; prezygapophyseal facets drop-shaped; zygosphene moderately convex in dorsal view; neural arch depressed and with dorsal edge modestly convex in posterior view; neural spine long and very low.

Variations of the morphology described above are mostly related to minor differences in terms of haemal keel shape (not widened posteriorly) and shape of the posterior edge of the neural arch.

DISCUSSION

The presence of a diastema is a character typical of the opisthoglyphous colubrines at our disposal for comparison: Malpolon Fitzinger, 1826 , Telescopus Wagler, 1830 , and Macroprotodon Guichenot, 1850 . Even if not totally congruent in morphology, the fragmentary maxilla of Capo Mannu is more similar to that of Macroprotodon than to those of Malpolon or Telescopus . The morphology of the fragmentary maxilla does not match with that of any known taxon so that is not demonstrated if it belongs to a new taxon or, more likely, if it is an unusual morphology of a taxon already described.

The colubrid trunk vertebrae devoid of hypapophysis are referred to an undetermined member of the working taxon “Colubrines” (sensu Szyndlar 1991a). The morphological uniformity of these vertebrae suggests that most of them probably belong to a single taxon, but it is not possible to exclude that some of the fragments belong to other taxa. Noteworthy is that the depressed neural arch and the long and low neural spine are two characters typical of taxa like Coronella Laurenti, 1768 and Telescopus .

Figures

FIG. 7. — Fossil remains of reptiles from Capo Mannu D1 Local Fauna (Sardinia): A-D, “Colubrines” indet: A, B, trunk vertebra (DSTC 6024), dorsal and posterior views; C, D, right maxilla (DSTC 6025), medial and ventral views; E, F, Vipera sp. trunk vertebra (DSTC 6026), dorsal and right lateral views. Scale bars: 2 mm.