Circoniscus hamatus, VAN NAME, 1936

Schmidt, Christian, 2007, Revision of the Neotropical Scleropactidae (Crustacea: Oniscidea), Zoological Journal of the Linnean Society 151, pp. 1-339 : 70

publication ID

https://doi.org/ 10.1111/j.1096-3642.2007.00286.x

persistent identifier

https://treatment.plazi.org/id/03858799-4279-FFAF-9B92-7871AAD9FCD5

treatment provided by

Felipe

scientific name

Circoniscus hamatus
status

 

CIRCONISCUS HAMATUS VAN NAME, 1936 View in CoL

Circoniscus hamatus Van Name, 1936 View in CoL – Paulian de Félice (1944); Souza & Lemos de Castro (1991 *); Boyko (1997); Leistikow & Wägele (1999 *); Schmalfuss (2003 *).

Circoniscus gaigei View in CoL (pro parte) – Lemos de Castro (1967); Schultz (1995).

Material examined

Type specimens: Five ♂, one ♀, slides with male pleopods 1 and 2 (paratypes, Guyana, Kamakusa , AMNH 6534 About AMNH ) .

Description

Male 9.0 × 4.8 mm.

Coxal plate 1 with schisma, the following coxal plates simple.

Cephalothorax: linea supraantennalis somewhat distant from sockets of the second antennae. Male pereiopod 7 on frontal face not with the modifications seen in C. ornatus (although poorly preserved and partly obscured by dirt, there seem to be no such ridges, or at least these are much more shallow than in the preceeding species). The ischium has a distinct conical protrusion on the caudal face of the distal margin (not drawn).

Pleopod 1 and 2 exopodites with dorsal respiratory fields. Male pleopod 1 exopodite rounded, not with a distinct distal lobe as in Ci. ornatus . Pleopod 1 endopodite apically curved outwards, with a row of small spine-shaped setae along the dorsal spermatic furrow. This row is broken by a short recurrent portion in the subapical position. (In the paratype, the small setae of the apical part could be seen at 400× magnification.) Male pleopod 2 exopodite with lateral margin evenly concave; distal lobe distinctly curved outwards. Inner margin of exopodite 2 with pectinate scales forming a hairy furrow.

Affinities

Circoniscus hamatus is probably the sister species of C. ornatus . On the male pleopod 1 endopodite, the dorsal row of small spine-shaped setae, which is broken by a short subapical transverse or recurrent portion, can be considered as a synapomorphy of both species.

Geographical distribution

Guyana, French Guiana.

Remark

Circoniscus hamatus View in CoL was cited in the synonymy of C. gaigei View in CoL by Lemos de Castro (1967) and Schultz (1995). As C. gaigei View in CoL auct. has proven to be C. ornatus View in CoL , whereas C. gaigei Pearse, 1917 View in CoL represents a different species, this synonymy cannot be maintained. Circoniscus hamatus View in CoL is provisionally regarded as a distinct species, because the known characters differ from both C. gaigei View in CoL and C. ornatus View in CoL . The examination of more specimens from the respective type localities may determine whether the specimens described as C. hamatus View in CoL belong to a distinct species, or are probably immature or abnormal specimens of C. gaigei View in CoL or C. ornatus View in CoL .

Kingdom

Animalia

Phylum

Arthropoda

Class

Malacostraca

Order

Isopoda

Family

Scleropactidae

Genus

Circoniscus

Loc

Circoniscus hamatus

Schmidt, Christian 2007
2007
Loc

Circoniscus hamatus

Van Name 1936
1936
Loc

Circoniscus hamatus

Van Name 1936
1936
Loc

Circoniscus hamatus

Van Name 1936
1936
Loc

C. hamatus

Van Name 1936
1936
Loc

Circoniscus gaigei

Pearse 1917
1917
Loc

C. gaigei

Pearse 1917
1917
Loc

C. gaigei

Pearse 1917
1917
Loc

C. gaigei

Pearse 1917
1917
Loc

C. gaigei

Pearse 1917
1917
Loc

C. gaigei

Pearse 1917
1917
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