Python sp.

Ivanov, Martin & Böhme, Madelaine, 2011, Snakes from Griesbeckerzell (Langhian, Early Badenian), North Alpine Foreland Basin (Germany), with comments on the evolution of snake faunas in Central Europe during the Miocene Climatic Optimum, Geodiversitas 33 (3), pp. 411-449 : 420-422

publication ID	https://doi.org/ 10.5252/g2011n3a2
persistent identifier	https://treatment.plazi.org/id/CA65878D-FFFC-FFAB-4520-FF4BFBD4E9C0
treatment provided by	Marcus
scientific name	Python sp.
status

Treatment

Python sp.

MATERIAL EXAMINED. — Griesbeckerzell 1a: 2 cervical vertebrae ( BSPG 1997 XIII 507, 508); 2 trunk vertebrae ( BSPG 1997 XIII 509, 510); 2 caudal vertebrae ( BSPG 1997 XIII 511, 512). — Griesbeckerzell 1b: 1 trunk vertebra ( BSPG 1997 XIII 513).

LOCALITY. — Griesbeckerzell 1a, 1b.

DESCRIPTION

Cervical vertebrae (Fig. 6A)

The vertebrae are markedly wider than long.In lateral view, the better preserved specimens are characterized by a high neural spine that is inclined posteriorly. The neural spine is about two times higher than long, although the distal tip of the spine is slightly damaged. The interzygapophyseal ridges are sharp and slightly upraised in caudal direction. Lateral foramina are large and may be situated in depressions. The straight or slightly dorsally vaulted subcentral ridges are short. The hypapophysis in one of the specimens is short, and its blunt distal tip indicates that the hypapophysis was inclined ventrally rather than postero-ventrally. Synapophyses are weakly divided into para- and diapophyses.

In dorsal view, the prezygapophyseal articular facets are subtriangular to oval and the prezygapophyseal processes are very short. The cranial margin of the zygosphene possesses an indistinct median lobe and small lateral lobes. The anterior base of the neural spine is situated at the base of the zygosphene. The interzygapophyseal constriction is weakly developed.

In ventral view, the centrum is triangular in shape with shallow subcentral grooves and short subcentral ridges. Subcentral foramina are small and situated close to the anterior ventral border of the cotylar rim.

In anterior view, the prezygapophyses are slightly tilted upwards. The neural arch is strongly arched and the neural canal is rounded. The cranial margin of the zygosphene is massive and straight. Deep depressions occur on both sides of the large cotyle of circular shape. Paracotylar foramina are absent.

In caudal view, the neural arch is strongly vaulted; the zygantral area is massive. Parazygantral foramina are absent.

Trunk vertebrae (Fig. 6B, C)

Vertebrae are characterized by a very low cl/naw ratio. In lateral view, the largest vertebra (BSPG 1997 XIII 509) is short and very high, although the neural spine is broken off at the base. The base of the synapophysis is large, but the distal tip is severely damaged. The synapophysis is well preserved in one smaller specimen (BSPG 1997 XIII 510), oblong in shape and indistinctively divided into a para- and diapophysis. The lateral foramina are large (or extremely large in one specimen) and situated in indistinct depressions. The interzygapophyseal ridges are conspicuous and their posterior portion bent in upward direction. The subcentral ridges are short and slightly dorsally vaulted.

In dorsal view, the interzygapophyseal constriction is only weakly expressed.The prezygapophyseal articular facets are triangular and the prezygapophyseal processes are not visible from above. The base of the neural spine begins to rise just at the level of the posterior margin of the prezygapophyseal facets. The posterior part of the neural arch is strongly vaulted and triangularly widened in caudal direction. The cranial margin of the zygosphene is nearly straight.

In ventral view, the centrum of the vertebrae is widely triangular in shape, with shallow subcentral grooves and blunt subcentral ridges. The subcentral foramina are large,may be enlarged antero-posteriorly, and are situated at the base of the wide haemal keel. The postero-ventral margin of the haemal keel may be relatively sharp. The damaged postzygapophyseal articular facets were most probably subtriangular.

In cranial view, the prezygapophyses are upraised and the cranial margin of the zygosphene is extremely thick. The neural arch is strongly vaulted. The neural canal is rounded with shallow lateral sinuses. Deep depressions occur at both dorsolateral sides of the circular cotylar rim. Paracotylar foramina are absent.

In caudal view, the zygantrum is massive; parazygantral foramina have not been observed. Measurements of the larger vertebra from Griesbeckerzell 1a (BSPG 1997 XIII 509) are as follows: cl = 9.32 mm; naw = 12.93 mm; cl/naw = 0.72. Measurements of the vertebra from Griesbeckerzell 1b (BSPG 1997 XIII 513): cl = 6.00 mm; naw = 8.62 mm; cl/naw = 0.70.

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FIG. 6. — Python sp. from the Middle Miocene (MN 6, base) of Griesbeckerzell 1a in lateral (l), dorsal (d), ventral (v) and cranial (cr) views: A, cervical vertebra (BSPG 1997 XIII 507); B, middle trunk vertebra (BSPG 1997 XIII 509); C, trunk vertebra (BSPG 1997 XIII 510); D, caudal vertebra (BSPG 1997 XIII 511). Abbreviations: hy, hypapophysis; ple, pleurapophysis; for other abbreviations, see Figure 4 View FIG . Scale bars: A, 2 mm; B, 5 mm; C, 5 mm; D, 2 mm.

Caudal vertebrae (Fig. 6D)

Two of the vertebrae come from the anteriormost section of the caudal region. In lateral view, the vertebral centrum is quite short. The neural spine lacks a dorsal thickening and is shifted to the posterior half of the neural arch. In dorsal view, the anterior margin of the zygosphene is almost straight or slightly concave. Prezygapophyseal articular facets are oval; prezygapophyseal processes are not visible. In ventral view, the bases of the broken off pleurapophyses are directed more or less in anterolateral direction. Haemapophyses are minute in one vertebra (BSPG 1997 XIII 512); the other vertebra (BSPG 1997 XIII 511) possesses an indistinct, wide haemal keel instead of haemapophyses. This suggests that the vertebra occurred in a very anterior (?anteriormost) position within the caudal region. The postzygapophyseal articular facets are damaged; they were probably subsquare in shape. In cranial view, the neural arch is vaulted. Deep depressions occur on both sides of the dorsoventrally slightly depressed cotylar rim. Paracotylar foramina are missing.

DISCUSSION

The absence of paracotylar foramina and large dimensions (see above) are typical features of the vertebrae of pythonine snakes. Although the absence of paracotylar foramina does also occur in boine snakes ( Szyndlar & Rage 2003), none of the Boinae reported from the European Miocene reaches the same dimensions as the snake from Griesbeckerzell. Assignment to the genus Python is further supported by the general correspondence in morphology of the massive vertebrae with vertebrae of other representatives of that genus. There is no substantial difference between the vertebrae of Python europaeus from the French localities Béon 1 (Early Miocene, Burdigalian, MN 4) ( Rage & Bailon 2005) and Vieux Collonges (early Middle Miocene, early Langhian, MN 5) ( Ivanov 2000; Szyndlar & Rage 2003) and the specimens from Griesbeckerzell (cf. Rage & Bailon 2005). In Python from these three sites: 1) the haemal keel is well defined by subcentral grooves that reach the cotyle; 2) the neural arch is markedly vaulted and upswept above the zygantrum; 3) the zygapophy- seal facets are weakly inclined; and 4) paracotylar foramina are absent. Minor differences are present with regard to the synapophyses, which are oblong rather than subsquare in Python sp. from Griesbeckerzell 1a and 1b and more distinctly shifted anteriorly than the synapophyses of Python europaeus from Vieux-Collonges. Moreover, Python sp. from Griesbeckerzell lacks a pointed small median projection of the zygosphene. The neural spine, which is an important feature with regard to the assignment to Python europaeus (it is lower than the neural spine of any other species of Python , cf. Szyndlar & Rage 2003) is broken off at the base. However, the base of the neural spine in one specimen from Griesbeckerzell 1b (BSPG 1997 XIII 513) indicates that this structure was relatively low. The fossil caudal vertebrae resemble those of Python europaeus with respect to the position and shape of the neural spine ( Szyndlar & Rage 2003). Although the fossil Python sp. from Griesbeckerzell 1a and 1b probably belongs to Python europaeus , the limited number of damaged vertebrae does not allow for more than identification at genus level.