Claustrathelges macdermotti, Williams & Boyko, 2016

Williams, Jason D. & Boyko, Christopher B., 2015, Abdominal bopyrid parasites (Crustacea: Isopoda: Bopyridae: Athelginae) of diogenid hermit crabs from the western Pacific, with descriptions of a new genus and four new species, Raffles Bulletin of Zoology 64, pp. 33-69 : 43-45

Claustrathelges macdermotti n. sp.

(Fig. 4)

Material examined. Australia: Mature holotype female (14.4 mm) ( MV J62893 ), infesting Cancellus typus (fide label), inhabiting stone, San Remo Channel, Victoria, 38°32’S 145°23’E, coll. I. Kirwan, March 1978 .

Description. Female (Fig. 4): Holotype body length 14.4 mm, maximal width 8.2 mm, head length 2.7 mm, head width 2.6 mm, pleon length 4.1 mm. Body longer than broad; pereon not distorted. All body regions and pereomeres distinctly segmented (Fig. 4A, B).

Head length and breadth subequal with nearly straight lateral margins, anterior margin slightly convex, posterior margin convex. Eyes lacking. Antennule (Fig. 4C) of three articles, setae on distal margin of distalmost two segments; antenna (Fig. 4C) of five articles, setae on distal margins of distalmost three segments. Maxilliped (Fig. 4G) with rounded anterior lobe, palp absent; posterior lobe subtriangular with short rounded spur. Barbula (Fig. 4D) of three lobes with highly digitate margins on each side.

Pereon of seven pereomeres, broadest across pereomere IV, tapering anteriorly and posteriorly. Pereomeres I–IV anteriorly concave and posteriorly convex, pereomere V nearly straight, pereomeres VI, VII anterior margin convex, posterior margin concave. No oostegites extended over head or produced posteriorly (Fig. 4A, B). Oostegites completely enclosing brood pouch (Fig. 4A); posteriormost oostegite with fringe of setae on posterior margin. First oostegite anterior lobe irregularly ovate with edges folded under, dorsal surface with medial region of ridges, posterior lobe with large ovate expansion and smaller, slightly tapering mesial extension, internal ridge with numerous digitations and larger digitate mesial lobe (Fig. 4E, F). All pereopods subequal, with all segments distinct (Fig. 4B, I, J). Pereopod I anterior to head, pereopods II,III parallel to head, no large gaps between pereomeres.

Pleon with five pleomeres, dorsal segmentation distinct. Pleomeres I–V (Fig. 4A, B, K) with elongate-ovate biramous pleopods and uniramous lateral plates, all arising from common peduncle; pleotelson lacking (Fig. 4K).

Male: unknown.

Type locality. San Remo Channel , Victoria, Australia .

Etymology. This species is named in honor of John J. McDermott (Emeritus Professor of Biology, Franklin and Marshall College, Pennsylvania, U.S.A.) for his considerable contributions to the biology and systematics of numerous marine invertebrates, including bopyrids. The specific name is spelled to conform to the ICZN Recommendations on the Formation of Names, Appendix D 21(a) (ICZN 1985: 197). Due to the necessity of synonymising the species we had earlier named for him, Pseudostegias macdermotti , in this paper, we felt it only fair to name a new species after him to make up for it. The taxonomist giveth and the taxonomist taketh away.

Distribution. Known only from the San Remo Channel, Victoria, Australia.

Host. Diogenidae : Cancellus typus.

Size Range (Length). Females: to 14.0 mm, males: unknown.

Remarks. The new species can be distinguished from its closest relatives in Falsanathelges by the characters given in the generic diagnosis. Cancellus hermit crabs were previously not known to bear any bopyrids. These hermits have an unusual choice of carcinoecia in that they are typically found living in calcareous rock, pumice, and other stones ( McLaughlin, 2008). These habitats would appear to be a relatively difficult type for abdominal bopyrids in regards to the high potential for scraping against the rough surface of the carcinoecia when the hermit crab abdomen is flexed.