Sorbinicapros is an extinct genus of acanthuriform ray-finned fish placed in the family Sorbinipercidae. Material of the fish is only known from the Pesciara site of Monte Bolca in Italy. It was a small, deep-bodied fish with a protractile jaw with largely molariform teeth. The exact placement of Sorbinicapros and its sister genus Sorbiniperca haven't been studied in recent years. In the past, these fish have been placed in a clade containing Caproidae, Zeiformes, and Tetraodontiformes but it is understood to not be a true clade in more recent years. The most recent placement showed it closely related to some Tetraodontiformes such as Parahollardia and Cretatriacanthus. There is one species within the genus: Sorbinicapros sorbiniorum.
History and naming The material assigned to Sorbinicapros was collected from the Pesciara site of Monte Bolca in Italy. There is a gap between the collection of both specimens, with the more recent of the two being collected in 1988. These specimens were later described by Alexandre F. Bannikov and James C. Taylor in 1999. The generic name of Sorbinicapros is in honor of Lorenzo Sorbini, a well known paleoichthyologist and previous director of the Museo Civico di Storia Naturale di Verona, along with the genus Capros. Similarly, the specific name "sorbiniorum" is in reference to both Lorenzo Sorbini and Chiara Sorbini.
Description Sorbinicapros is a small, deep-bodied fish with a short but robust caudal peduncle known from two complete specimens. The holotype specimen (MCSNV VR. 27634/27635) has a standard length of 88 millimetres (3.5 in) while the paratype (MCSNV VIII.C9/10) is slightly larger, having a standard length of 94 millimetres (3.7 in). Both specimens are represented by both a part and counterpart. Compared to the relatively stout body of the fish, the caudal fin of Sorbinicapros is very large, measuring 46 millimetres (1.8 in) in the paratype. The deepest portion of the body is located at the level of the first dorsal, being 66-71% of the standard length.
Skull As seen with other fish with body lengths that are shorter proportionally, the head of Sorbinicapros makes up a decent amount of its body length. This equals about 38.6% and 36.2% of the standard lengths of the holotype and paratype respectively. Also similar to other deep-bodied fish, the skull of the fish is deep and triangular in shape. The orbits of the fish is small and placed fairly high on the skull. Similar to other portions of the skull, the deep neurocranium of Sorbinicapros is not completely preserved. The parasphenoid is a straight bone located above the orbit and possesses a large flange on the ventral portion. The ethmoid region of the neurocranium is long and ossified. Though preserved in specimens, the exact anatomy of the supraoccipital is poorly known. The jaws of Sorbinicapros are made up of robust bones that take up is large amount of the head (about 64.7%) and is slightly pointed downwards. The premaxilla is a large, L-shaped bone with a long ascending process. Though not preserved, the maxilla was most likely closely articulated with the previously mentioned bone. The mandible deep and triangular, resulting in the symphysis being much more shallow than the posterior portion. Sorbinicapros has a heterodont dentition. This is best preserved on the premaxilla which possesses multiple series of teeth with fifteen teeth making up the main series. The anterior-most teeth are cone-shaped and much larger than the others. The other teeth on the premaxilla along with those seen on the mandible, are much shorter and molariform. The large ascending process on the premaxilla also suggests that Sorbinicapros had a protractile jaw. The suspensorium of the fish is poorly preserved with the only two bones being visible being the triangular quadrate and hyomandibular. Very small portions of the ectopterygoid and metapterygoid can be seen in the holotype and paratype respectively. The point of jaw articulation is located under the front edge of the orbit. The branchial arches of Sorbinicapros are not well preserved, though some features are able to be made out. These bones are saber-shaped and there most likely would have only been a maximum of five. The hyoid is also poorly preserved so no features of the anatomy can be made out. The opercular region of the fish is very narrow and deep. It is preserved in specimens though it is hard to make out the exact bones. Based on the known material, the region has no serrations on the posterior edge. The preopercle seems to be a narrow, slightly anteriorly-curving bone.
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