Family ANTARCTURIDAE Poore, 2001

Chaetarcturus crosnieri

© Copyright from Poore 1998.

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Introduction

Many undescribed Australian antarcturid species are known from museum collections. The only named species were described as, or have been placed in the genus 'Microarcturus', but this name is unavailable under ICZN (1999) Art. 13.3 (Poore 1991). These animals are certainly antarcturids rather than arcturids, and members of several genera, but they remain incertae sedis until a generic revision of the family is completed. The family, of about 16 genera, includes many deep-water and cold-water species. The diagnosis is from Poore (2001). Poore (2015) removed one of the unplaced names, Arcturus serrulatus Whitelegge, 1904, to become the type species of a new genus, Halearcturus.

Diagnosis

Body flexed between pereonites 4 and 5. Head and pereonite 1 fused. Pereonite 4 of similar length to pereonite 3. All pleonites fused into pleotelson. Body strongly spinose with at least dorsal and dorsolateral pairs of spines, often dominated by pair near end of pleotelson; pleotelson without dorsolateral ridges ending in mediodorsal posterior spine. Dorsal coxal plates 2–7 obsolete, bases of pereopods exposed. Mouthparts and pereopod 1 visible in lateral view. Eyes well developed, or reduced or lost.

Antenna 2 flagellum multiarticulate, or of 2–3 articles plus distal claw. Pereopod 1 a gnathopod, pereopods 2–4 elongate, differentiated from ambulatory pereopods 5–7. Pereopod 1 dactylus evenly curved along anterior margin, evenly tapering. Pereopods 2–4 with paired long setae along posterior margins evenly and well developed; with prominent dactylus, unguis short; pereopod 4 similar to pereopod 3. Pereopods of males without dense fur of fine setae. Uropodal exopod (smaller ramus) tapering (with terminal setae only), more than half as long as endopod (when present).

Oostegites 1–4 functional, 5 absent; 1–4 supported by coxal lobes. Penes fused as a single penial plate; penial plate apically simple or barely slit. Pleopod 1 peduncle more elongate than on other pleopods; with marginal setae on rami longer than or equal to length of rami. Pleopod 1 exopod of male thickened and with groove on posterior face, with few simple setae along straight lateral margin; with groove on posterior face of exopod ending distolaterally or laterally on simple margin. Pleopod 2 of male with appendix masculina about as long as endopod, basally less than half width of endopod.

General References

Poore, G.C.B. 1991. Neoarcturus Barnard, 1914: Diagnoses of the genus and its type species and substitution for the nomen nudum 'Microarcturus' Nordenstam, 1933 (Isopoda, Arcturidae). Annals of the South African Museum 101: 1-8

Poore, G.C.B. 2001. Isopoda Valvifera: diagnoses and relationships of the families. Journal of Crustacean Biology 21: 205-230

Poore, G.C.B. 2015. Halearcturus, a new genus of Antarcturidae Poore, 2001 (Crustacea: Isopoda: Valvifera) with a key to genera of the family. Memoirs of Museum Victoria 73: 13-18 (key to genera)

History of changes