Description

The main confusion among WNP squatinids lies in differentiating S. formosa and S. nebulosa from one another. The main character used in the past to differentiate these two species was the number of dermal lobes at the corners of the mouth (Chen 1963, Nakabo 2002, Compagno 2005 a). Based upon our examination, this character does not appear to be robust in separating these species. Although all S. formosa individuals studied had one dermal lobe, S. nebulosa specimens had one or two lobes, invalidating this character as a method of separating the two species. Additionally, the number of dermal lobes was often difficult to determine since differentiation between lobes is often vague and these lobes are susceptible to damage during capture and or preservation of specimens. A combination of characters should be used to identify individuals of these two species, since the differences are subtle and a great deal of overlap exists among many characters. The best characters available, based on our findings, appear to be the shape of the caudal pelvic and dorsal fins, the ratio of standardized pelvic girdle distance with the standardized head length, and the shape and height of the upper lip arch. The upper lip arch appears to be of particular value as a field character. It is a feature that is not prone to damage and is easy to assess quickly in the field. More specimens are needed to assess the utility of this character but it appears to be useful for all WNP squatinids. Based on the key characters presented herein, we provide the following key to the WNP squatinids:

Common Names

Taxonomic Hierarchy

Kingdom: Animalia

Phylum: Chordata

Class: Elasmobranchii

Order: Squatiniformes

Family: Squatinidae

Genus: Squatina

Species: Squatina Duméril, 1805