Hyla, Laurenti, 1768

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 : 365-366

Hyla gr. H. arborea (Linnaeus, 1758) ( Fig. 3 C-G)

MATERIAL EXAMINED. — Mandible: 1; scapula: 3; humerus: 2; ilium: 8; femur: 2; trunk vertebra: 3; sacral vertebra: 1; urostyle: 2.

DESCRIPTION

A tiny mandible is characterized by a posteriorly directed “tubercle” on the medial edge of the coronoid process.

One of the three scapulae is well preserved: it is a triradiate element with an elongated and narrow pars suprascapularis, and narrow subequal pars acromialis and processus glenoidalis; the inner surface of these structures is completely smooth.

The humeri fragments show a straight diaphysis with an eminentia capitata slightly shifted toward the radial epicondyle; radial and epicondylar ridges are well developed; the fossa cubitalis is relatively deep and markedly open in lateral direction.

Seven right ilia and one left element are characterized by a tuber superior that develops a distinct tubercle in lateral direction and by a preacetabular zone expanded in a wide blade that involves dorsally the ilial shaft and ventrally the pars descendens ilii; the ilial shaft is approximately cylindrical and devoid of crista dorsalis.

Two fragmentary lightly-built femora show a delicate crista femoris in the proximal area.

All the trunk vertebrae show a remarkably wide neural canal and a proportionally tiny procoelous centrum.

The sacral vertebra is procoelous with a double posterior condyle; the partly preserved lateral apophyses clearly indicate that they were rather constricted at the base and not cylindrical; a hint of neural ridge is developed along the posterior margin of the neural arch.

Two urostyles share the presence of rounded cotylar cavities for the sacral condyles; the neural arches are broken off at the basis.

DISCUSSION

The skeletal morphology of the European tree frogs is quite characteristic and therefore their fossil remains are easily identifiable at genus rank. The morphology of the ilium ( Böhme 1977; Bailon 1999), as well as of all the other skeletal elements is congruent with that of the corresponding elements of extant species of genus Hyla . Due to the unreliability of the osteological characters that were presumed to allow distinction among the European species, the fossil remains from the Capo Mannu D1 LF are referred only at species group rank,named after the most representative species (for a discussion see Delfino & Bailon 2000).

Figures

FIG. 3. — Fossil remains of amphibians from Capo Mannu D1 Local Fauna (Sardinia): A, Discoglossus sp., rigth ilium (DSTC 6005), lateral view; B, cf. Bufo gr. B. viridis, left ilium (DSTC 6006), lateral view; C-G, Hyla gr. H. arborea; C, rigth ilium (DSTC 6007), lateral view; D, rigth ilium (DSTC 6008), lateral view; E, left humerus (DSTC 6009), ventral view; F, left scapula (DSTC 6010), lateral view; G, presacral vertebra (DSTC 6011), dorsal view. Scale bar: 2 mm.