Squamophis, Okanishi, Masanori, O'Hara, Timothy D. & Fujita, Toshihiko, 2011

Okanishi, Masanori, O'Hara, Timothy D. & Fujita, Toshihiko, 2011, A new genus Squamophis of Asteroschematidae (Echinodermata, Ophiuroidea, Euryalida) from Australia, ZooKeys 129, pp. 1-15 : 4

Genus Squamophis gen. n.

Type species:

Asteroschema amamiense Okanishi & Fujita, 2009

Other included species:

Squamophis albozosteres sp. n.

Diagnosis.

Aboral periphery of the disc and aboral base of the arms covered completely by contiguous plate-shaped epidermal ossicles. Single-layered radial shields completely covered by epidermal ossicles. No ventral arm plates on middle to distal sections of the arms. Relative length of the longest arm spines the same length as the corresponding arm segment throughout the arms.

Etymology.

The generic name is a masculine noun in the subjective case, a compound of Latin, squama (prefix, meaning “scale”) referring to the plate-shaped epidermal ossicles on their body and the Greek ophis (masculine noun, meaning “snake”), referring to their snake-like arms.

Remarks.

( Okanishi and Fujita (2009, 2011a) examined internal ossicles of many species of Asteroschema and revealed that Asteroschema amamiense differed in having both single-layered radial shields and contiguous plate-shaped epidermal ossicles, on the aboral periphery of the disc and the aboral base of the arms, that are similar in shape and arrangement to species of Astrocharis . Furthermore, a recent molecular phylogenetic analysis ( Okanishi et al. in press), based on mitochondrial (16S) and nuclear ribosomal RNA genes (18S, 28S), also showed that Squamophis albozosteres sp. n. (as Asteroschema sp.) and Astrocharis monospinosa form a clade that was separated from the two other species of Asteroschema that were sequenced, Asteroschema ajax A. H. Clark, 1949 and Asteroschema ferox Koehler, 1904. This new species also had single-layered radial shields and contiguous plate-shaped epidermal ossicles. However, both Asteroschema amamiense and Squamophis albozosteres differed from Astrocharis species in having covered radial shields and relatively short arm spines that are only as long as the corresponding arm segment. This morphological and molecular phylogenetic evidence suggests to us that these two species should be distinguished at a generic level from the other species of Asteroschema and Astrocharis . Therefore, we describe a new genus Squamophis for these two species. The distinguishing characters for the new genus are given in Table 1.

The genus Squamophis currently comprises two species: Squamophis amamiensis (Okanishi & Fujita, 2009) from south-western Japan, 167-168 m and Squamophis albozosteres sp. n. from north-western Australia, 95-108 m. Asteroschema capense Mortensen, 1925 and Asteroschema igloo Baker, 1980 may also be related to Squamophis amamiensis , based on the similarity of shapes and arrangement of epidermal ossicles ( Okanishi and Fujita 2009). However, we have not examined the nature of radial shields on their type specimens and hence we refrain from transferring these two species to the new genus at this time.