Falsanathelges mariae, 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 : 45-49

Falsanathelges mariae n. sp.

(Figs. 5–7)

Material examined. Philippines: Mature holotype female (7.8 mm), mature allotype male (2.7 mm) ( USNM 1283372), infesting male Calcinus gaimardii (4.4 mm SL), inhabiting unidentified shell, Oriental Mindoro, Puerto Galera, La Laguna Beach, coll. JDW, 19 July 1997; mature paratype female (5.6 mm), mature paratype male (3.1 mm) ( USNM 1283373), infesting female Calcinus latens (3.4 mm SL), inhabiting shell of Peristernia incarnata , Cebu, Olango Island and Sulpa Islet, coll. JDW, 9 July 1997; immature paratype female (8.34 mm), mature paratype male (2.04 mm) ( ZRC 2015.0499), infesting intersex Clibanarius merguiensis (2.5 mm SL), inhabiting shell of Clypeomorus sp. , Oriental Mindoro, Puerto Galera, Coco Beach, coll. JDW, 12 January 1999; mature paratype female (5.03 mm), mature paratype male (3.47 mm) ( ZRC 2015.0500), infesting female C. gaimardii (3.0 mm SL), inhabiting shell of Cypraea sp. , Oriental Mindoro, Puerto Galera, Coco Beach, coll. JDW, 14 January 1999; mature female (6.33 mm) with Cabirops female, mature male (2.04) (pers. coll.), infesting female Calcinus minutus (2.8 mm SL), inhabiting shell of Peristernia nassatula (Lamarck) , Aklan, Boracay, Rocky Beach, coll. JDW, 12 April 1999; mature female (7.74 mm) ( ZRC 2015.0501), infesting male C. merguiensis (2.26 mm SL), inhabiting unidentified shell, Puerto Galera, La Laguna Beach, coll. JDW, 17 June 2000; mature female (8.41 mm), mature male (2.53 mm) ( USNM 1283374), infesting female C. gaimardii (3.3 mm SL), inhabiting unidentified shell, Puerto Galera, La Laguna Beach, coll. JDW, 28 July 1997; mature female (7.38 mm), mature male (2.61 mm) ( USNM 1283375), infesting female C. minutus (1.8 mm SL), inhabiting unidentified shell, Bataan, Mabayo, coll. JDW, 21 February 1999; mature female (9.67 mm), mature male (3.0 mm on SEM stub) ( USNM 1283376), infesting male C. minutus (3.6 mm SL), inhabiting unidentified shell, Bataan, Mabayo, coll. JDW, 21 February 1999. Taiwan: Mature female (7.8 mm, damaged), mature male (2.3 mm) ( USNM 1283377), infesting female Calcinus guamensis (3.6 mm SL), inhabiting unknown shell, Siadao, Pingtung, coll. R. Yoshida, 26 July 2011; mature female (7.4 mm), mature male (2.5 mm) ( USNM 1283378), infesting female C. guamensis (3.7 mm SL), inhabiting unknown shell, Houwan, Pingtung, coll. R. Yoshida, 27 July 2011; mature female (6.4 mm) ( USNM 1283379), infesting male C. guamensis (2.5 mm SL), inhabiting unknown shell, Gonggang, Green Island, coll. R. Yoshida, 24 June 2013.

Description. Female (Fig. 5): Holotype body length 7.8 mm, maximal width 2.8 mm, head length 0.9 mm, head width 0.9 mm, pleon length 3.5 mm. Body longer than broad; pereon anteriorly distorted dextrally. All body regions and pereomeres distinctly separated (Fig. 5A, B).

Head length and breadth subequal with convex lateral margins, anterior margin deeply concave, posterior strongly convex. Eyes lacking. Antennule (Fig. 5C) of three articles, setae on distal margin of distalmost two segments; antenna (Fig. 5D) of five articles, setae on distal margins of distalmost three segments. Maxilliped (Fig. 5E) with subtriangular anterior lobe, palp absent; posterior lobe subtriangular with long thin spur. Barbula (Fig. 5E, H) of two short lobes with digitate margins on each side.

Pereon of seven pereomeres, pereomeres III–VII broadest, subequal in width. Pereomeres I–III anteriorly concave and posteriorly convex, pereomeres IV–VII anteriorly convex, posteriorly concave. Oostegites I slightly extended over head; no oostegites produced posteriorly (Fig. 5A, B). Oostegites completely enclosing brood pouch (Fig. 5B). First oostegite anterior lobe irregularly ovate with edges folded under, posterior lobe with large ovate expansion and smaller, recurved mesial extension, internal ridge with numerous digitations and larger digitate mesial lobe (Fig. 5F, G). All pereopods subequal and with all segments distinct (Fig. 5B, I, J). Pereopod I anterior to head, pereopods II, III parallel to head, no large gaps between pereomeres. All pereopods with elongate bases and ischia, pronounced lobe present on each basis (Fig. 5I).

Pleon with six pleomeres, dorsal segmentation distinct. Pleomeres I–V (Fig. 5A, B) with elongate-ovate biramous pleopods and uniramous lateral plates; pleotelson with uniramous uropods (Fig. 5A).

Male (Figs. 6, 7): Body length 2.7 mm, maximum width 1.1 mm, head length 0.3 mm, head width 0.6 mm, pleon length 0.8 mm. Head subovate, widest medially, distinct from pereomere I, mediodorsal cephalic slits present ( Fig. 7B ). Small eyes mediolaterally. Antennule of three articles (Figs. 6D, 7A), antenna of five articles (Figs. 6D, 7A), setae on distal region of all segments except for basal antennal article, proximal two articles of antennule and antenna with marginal scales. Oral cone with scales on surface ( Fig. 7C ). Pereomere V broadest, tapering anteriorly and posteriorly, but tapering more marked anteriorly. Pereomeres I–IV directed laterally with rounded distal margins, V–VII with slight posteriolateral curvature. Small patches of pigmentation on pereomeres I, III, IV. All pereopods (Figs. 6B, E, F, 7A, D–F), subequal in size, all articles distinctly separated, dactylus of pereopods I–II larger than those of pereopods, ventral margin of carpus, merus, and edge of propodus with few stout setae, ventral margin of carpus and edge of propodus with few low scales (Figs. 6E, F, 7D, E). Pleon tapering posteriorly, all pleomeres fused but with variable degrees of lateral indication of segmentation (Figs. 6A, C, 7F); posterior margin rounded. No midventral tubercles, pleopods, or uropods (Figs. 6B, C, 7F).

Type locality. Philippines, Oriental Mindoro, Puerto Galera: La Laguna Beach (13°30’N, 120°57’E) .

Etymology. Named for Maria Spector, the wife of the second author, for her continual support and encouragement.

Distribution. Known from Oriental Mindoro and Cebu provinces in the Philippines and Taiwan.

Hosts. Diogenidae : Calcinus gaimardii , C. guamensis , C. latens , C. minutus , and Clibanarius merguiensis .

Size Range (Length). Females: to 9.67 mm, males: to 3.47 mm.

Remarks. The genus Falsanathelges was erected for Anathelges muelleri Nierstrasz & Brender à Brandis, 1931 from Malaysia and Indonesia on the hosts Clibanarius infraspinatus ( Hilgendorf, 1869) and Calcinus lineapropodus Morgan & Forest, 1991 , respectively. The present specimens are very similar to those of F. muelleri , but differ in the following characters: female uropods uniramous (biramous in F. muelleri ), female pleopods and lateral plates slender (broadly ovate in F. muelleri ), male pereomeres markedly broader posteriorly (all pereomeres subequal in width in F. muelleri ). The presence of uniramous uropods in the new species, which otherwise is clearly closely related to F. muelleri , necessitates a modification in the key to athelgine genera given by Boyko & Williams (2003).

Calcinus gaimardii has never been reported to host bopyrids but in the present study is found to host three abdominal bopyrid species (see Table 2). One female of Falsanathelges mariae n. sp. from the Philippines contained a hyperparasitic isopod ( Cabirops sp. ) in the brood chamber.

Figures

Fig. 7. Falsanathelges mariae n. sp. scanning electron micrographs of male paratype, USNM 1283376 (A–F). A, ventral view of anterior end; B, dorsal view of head, showing cephalic slits (presumptive sensory structure, see Bourdon et al., 1981); C, oral cone; D, left pereopod 1; E, left pereopod 7; F, seventh pereomere and pleon. Scale bars = 400 µm [A, B], 20 µm [C], 100 µm [D], 200 µm [E], 500 µm [F].