Capropygia

Capropygia
Conservation status
Least Concern  (IUCN 3.1)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Tetraodontiformes
Family:	Aracanidae
Genus:	Capropygia Kaup, 1855
Species:	C. unistriata
Binomial name
Capropygia unistriata (Kaup, 1855)
Synonyms
Aracana unistriata Kaup, 1855

Capropygia is a monospecific genus of marine ray-finned fish belonging to the family Aracanidae, the deepwater boxfishes or temperate boxfishes. The only species in the genus is the black-banded pigmy boxfish (Capropygia unistriata), also known as the spiny boxfish which is endemic to southern Australia.

Taxonomy

Capropygia was first proposed as a subgenus of Aracana in 1855 by the German zoologist Johann Jakob Kaup when he described its only species Aracana (Capropygia) unistriata. Kaup did not give a type locality for A. unistriata but it is lilely to be southeasern Australia. The 5th edition of Fishes of the World classifies this taxon in the family Aracanidae which is in the suborder Ostracioidea within the order Tetraodontiformes.

Etymology

Capropygia compounds capros, meaning "wild boar", with pygia, which means "rump" or "buttocks", Kaup described it as “Viewed from behind, it resembles the rear part of a well-fed pig”. The specific name unistriata', means one stripe", an allusion to the dark strip running from the eye to the tail.

Description

Capropygia has a deep body is short and has a circular profile and a rather hexagonal cross section, with rdges on the back and belly and on the upper and lower flanks. The lower flank ridge has a flattened spine at the rear and the upper flank ridge has a large spine at its middle. The moderately small head has a straight dorsal profile with a small terminal mouth and eyes positioned high on the head. The mouth has fleshy lips aotha single row of cloely set curved teeth in each jaw. The body is encased in a stiff carapace consisting of large, hexagonal scales, each plate being sculpted with fine tubercles which join the scales together. The caudal peduncle has a rear ring of these scales and some isolated scales at its front. There is a single dorsal fin, with 12 soft rays, located far back on the body and has a short base. The anal fin is opposite the dorsal fin and has 12 or 13 soft rays. The caudal fin is rounded with 11 soft rays and the small fan-like pectoral fins contain 12 soft rays. The overall color is pale yellowish-brown to tan or greyish-brown, typically with a wide black stripe along the flanks, in some specimens this may be indistinct, black lips, and the ridge spines and fin bases have black blotches or are surrounded with black. The black-banded pigmy boxfish has a maximum published total length of 12 cm (4.7 in).

Distribution and habitat

Capropygia is endemic to southern Australia where it is found from Cape Conran, Victoria west to Rottnest Island in Western Australia. It is found on deeper reefs on the continental shelf,at depths between 60 and 200 m (200 and 660 ft). It is occasionally washed intio inshorewaters by storms, when it can appear in tidal pools.

References

• Spiny Boxfish, Capropygia unistriata (Kaup 1855) @ fishesofaustralia.net.au