Bavarioboa sp.
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publication ID |
https://doi.org/ 10.4202/app.2011.0075 |
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persistent identifier |
https://treatment.plazi.org/id/03E17050-FFFE-5206-8B3C-5C0EBDDBFA79 |
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treatment provided by |
Felipe |
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scientific name |
Bavarioboa sp. |
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Fig. 3 View Fig .
Material.—AUNHL IZ100401a, anterior trunk vertebra ( Fig. 3A View Fig ); AUNHL IZ100401b, middle trunk vertebra ( Fig. 3B View Fig ).
Description.—The vertebra from the middle trunk portion of the column (AUNHL IZ100401b) is almost completely preserved except for slightly eroded tips of the prezygapophyseal processes and posterior surface of the condyle. The centrum length (measured as the distance between the cotyle lip and the end of the condyle) is 5.0 mm approximately; the centrum width (the width of the interzygapophyseal constriction) is 7.1 mm.
In lateral view, the vertebra is slightly higher than long. The neural spine is approximately as high as long, with anterior and posterior margins vertical, occupying one half the length of the neural arch, and beginning above the zygosphenal articular facets. The anterodorsal portion of the neural spine is slightly rounded. The lateral foramina are small but distinct. The paradiapophyses are subsquare in shape, somewhat higher than long anteroposteriorly, with indistinct subdivision into para− and diapophyseal portions. The subcentral ridges are prominent. The haemal keel is distinct, with its ventral margin straight.
In dorsal view, the vertebra is distinctly wider than long. The notch in the posterior border of the neural arch is moderately deep. The interzygapophyseal constriction is well expressed. The neural spine is moderately thick. The zygosphene is provided with three indistinct and wide lobes. The long axis of prezygapophyseal facets is weakly oblique. The prezygapophyseal articular facets are subtriangular in shape. The prezygapophyseal processes are not visible.
In ventral view, the centrum is distinctly wider than long. The haemal keel looks like a biconcave lens owing to the presence of a distinct constriction, at the level of the subcentral foramina, and prominent broadenings at the anterior and posterior ends; it is triangular in cross section. The subcentral grooves are relatively deep. The subcentral foramina are small but distinct. The postzygapophyseal articular facets are subtriangular in shape. The prezygapophyseal processes are weakly developed (their tips are lost).
In anterior view, the zygosphene is slightly concave dorsally. It is as wide as the cotyle, the latter being moderately flattened dorsoventrally. The prezygapophyses are located clearly above the floor of the neural canal and are weakly inclined. The paradiapophyses project downwards slightly beyond the cotyle lip. The paracotylar foramina are absent.
In posterior view, the neural arch is weakly vaulted. The neural spine is moderately thick. The condyle is slightly flattened dorsoventrally.
The other vertebra (AUNHL IZ100401a), as characteristic of the cervical region of the column, is distinctly higher than long, the neural arch is more vaulted in comparison with the middle trunk vertebra, the neural spine is shorter and higher, and the haemal keel is replaced by a hypapophysis. The distal portion of the latter structure is broken off, but the preserved base indicates that the hypapophysis was prominent.
Remarks.—To some extent, the Mendikdere fossils resemble trunk vertebrae of the Erycinae (another subfamily of the family Boidae ), in particular those of the living Eryx –Gongylophis complex. However, vertebral centra of the latter snakes are (usually) relatively shorter, neural arches much more depressed, prezygapophyseal processes longer, and haemal keels either underdeveloped or (if distinct) uniform in width (ZS, unpublished observations).
The fossil remains display clearly diagnostic features of the extinct genus Bavarioboa —see Szyndlar and Rage (2003) for detailed diagnoses of members of Bavarioboa and comparisons with other, extant and extinct, genera of the Boinae . More specifically, the vertebrae from the Mendikdere Formation most resemble several Late Oligocene and Miocene members of the genus, in particular B. crocheti from the French Late Oligocene (MP 28). Especially, the Turkish Bavarioboa and B. crocheti share the peculiar biconcave−lens−like haemal keel, the feature not observed in other species of the genus; besides, both snakes are characterized by weakly vaulted neural arches. However, the material from the Mendikdere Formation, consisting of two vertebrae only, is neither sufficient for the identification to specific level nor for the description of a new species. What is more, precise comparisons of the Turkish fossils with B. crocheti make great difficulties, considering that the latter is characterized by a very broad spectrum of intraspecific variation in its vertebral morphology ( Szyndlar and Rage 2003).
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