Parathelges enoshimensis Shiino, 1950

An, Jianmei, Williams, Jason D. & Yu, Haiyan, 2011, Three abdominal parasitic isopods (Isopoda: Epicaridea: Bopyridae: Athelginae) on hermit crabs from China and Hong Kong, Journal of Natural History 45 (47 - 48), pp. 2901-2913 : 2904-2906

Parathelges enoshimensis Shiino, 1950

( Figure 2 )

Parathelges enoshimensis Shiino, 1950: 162–164 , fig. 5. Codreanu 1961: 137 (list). Markham 1972: 58 (list), 76 (key). Kim and Kwon 1988a: 213–215, fig. 8. Kim and Kwon 1988b: 215. Kazmi and Markham 1999: 884. Markham 2003: 74 (list). McDermott et al. 2010: 11 (table). Markham 2010: 183.

Material examined

Infesting Spiropagurus sp. South Sea, Stn 6142, 18 ◦ 00 ′ N, 111 ◦ 00 ′ E, 96 m, 8 April 1960, Yongliang Wang coll., 1 ♀, CIEA614201 , 1 ♂, CIEA614202 .

Description of female ( CIEA 614201)

Length (not including pleopods and uropods) 13.2 mm, maximal width 7.24 mm, head length 1.49 mm, head width 1.69 mm. All body regions and segments distinct. No pigmentation ( Figure 2A ).

Head pentagonal, anterior edge straight, posterior edge rounded, with short frontal lamina. Without eyes. Antennule and antennae of three and six articles, respectively, all articles without setae ( Figure 2C ). Maxilliped lacking palp, with long and sharp plectron ( Figure 2D ). Barbula with three small falcate projections on each side, flat middle region ( Figure 2E ).

Pereon almost completely segmented dorsally, with mid-dorsal ridge. Pereon broadest across pereomere 4. Pereomere 1 bisected by head, pereopod 1 anterior to head; pereomere 2 surrounding head, pereopod 2 beside head. Posterolateral flaps on pereomeres 2–7. Pereomere 5 markedly longer than others. Oostegites almost enclosing highly vaulted brood pouch ( Figure 2B ). Oostegite 1 ( Figure 2F, G ) greatly extended, anterior article twice as long as posterior articles, digitate internal ridge, posterior article tapering to rounded point. Pereopods small, bent; ischium with rounded projection ( Figure 2H ).

Pleon of five pleomeres, first four bearing pedunculate biramous foliate pleopods, all of similar structure, with venation on the surface ( Figure 2A ). Pleomere 5 short, terminating in pair of small uniramous uropods.

Description of male ( CIEA 614202)

Length 5 mm, maximal width across pereomere 7, 2.16 mm, head length 0.56 mm, head width 1.39 mm, pleonal length 1.56 mm ( Figure 2I, J ).

Head oval, nearly three times as broad as long ( Figure 2I ), fused with pereomere 1. Colourless eyes near posterior margin. Antennule and antennae of three and five articles respectively, distal articles setose ( Figure 2K ).

Pereomeres distinctly segmented, almost equally wide, with truncate margins. Last two pereomeres with small midventral projections ( Figure 2J ). Pereopod 1 with meri and carpi fused, pereopods 1 and 2 with much longer dactyli than posterior pereopods ( Figure 2L ).

Pleomeres fused, pleomere 1 indicated by lateral enlargement. Middle region of pleon distinctly concave. Four pairs of low, oval tuberculate structures (remnant pleopods) on pleon ( Figure 2J ).

Remarks

Parathelges enoshimensis has been reported from Japan ( Shiino 1950) and Korea ( Kim and Kwon 1988a, b). The present specimens conform well to Shiino’s syntypes except in some minor characters that have been shown to be variable in bopyrids (e.g. venation of pleopods, lack of pigment in males). Parathelges enoshimensis is very similar to Parathelges weberi Nierstrasz and Brender à Brandis, 1923 and further investigations may show that the species are conspecific. Markham (2010) considered Parathelges weberi and Parathelges whiteleggei Nierstrasz and Brender à Brandis, 1931 to be junior synonyms of Parathelges aniculi ( Whitelegge, 1897) . However, this species complex is in need of further study because specimens from the Philippines call into question the identity of Parathelges weberi , which appears to be distinct from Parathelges aniculi (Williams and Boyko in preparation).

Range and hosts

Japan on Pagurus sp. ( Shiino 1950) ; South Sea, China on Spiropagurus sp. (herein); Korea on Pagurus dubius (Ortmann) and Pagurus filholi (de Man) ( Kim and Kwon 1988a) .

Figures

Figure 2. Parathelges enoshimensis Shiino, 1950. (A–H) Female (CIEA614201):(A) dorsal view; (B) ventral view; (C) right antennule and antennae; (D) right maxilliped, external view; (E) right side of barbula; (F) right oostegite 1, external view; (G) right oostegite 1, internal view; (H) right pereopod 5. (I–L) Male (CIEA614202): (I) dorsal view; (J) ventral view; (K) right antennule and antennae; (L) left pereopod 1. Scale bars: 1 mm for A, B; 0.12 mm for C, E; 0.27 mm for D, H; 0.43 mm for F, G; 0.17 mm for I, J; 0.10 mm for K, L.