Aporobopyrus retrorsa Richardson, 1910

An, Jianmei, Boyko, Christopher B. & Yu, Haiyan, 2012, New records and hosts for three species of pseudionine bopyrids (Crustacea: Isopoda: Bopyridae) parasitizing munidid squat lobsters (Crustacea: Anomura: Munididae) in Philippine waters, Journal of Natural History 46 (45 - 46), pp. 2881-2888 : 2883-2884

Aporobopyrus retrorsa Richardson, 1910

( Figures 2 , 3 )

Pseudione retrorsa Richardson, 1910: 37–38 , fig. 35; Nierstrasz and Brender à Brandis, 1923: 78 (list); Shiino, 1958: 35 (comparison with P. lenticeps ).

Pseudione lenticeps Shiino, 1958: 34–35 , fig. 3; Shiino, 1972: 7 (list).

Aporobopyrus lenticeps, Adkison, 1988: 579 (new combination); Saito et al., 2000: 35 (list).

Aporobopyrus retrorsa, Boyko, 2004: 680–684 , figs. 2–4 (new combination, synonymy); Kazmi and Boyko, 2005: 8; Williams and Madad, 2010: 26–27; Boyko and Williams, 2011: 285; Boyko et al. 2012: 6, 17–19, 25, 28 (list).

Material examined

Infesting Munida philippinensis Macpherson and Baba, 1993 , Philippine waters, 14 ◦ 00’ N, 120 ◦ 17’ E, 175–184 m, 20 September 1985, coll. Yongliang Wang, 5 ♀, 5 ♂ (CI1081y).

Infesting Munida kuboi Yanagita, 1943 , Philippine waters, 14 ◦ 00’ N, 120 ◦ 17’ E, 175–184 m, 20 September 1985, coll. Yongliang Wang, 2♀, 2 ♂ (CI1081z).

Remarks

Richardson (1910) described Pseudione retrorsa infesting an unidentified squat lobster (later identified as Munida andamanica Alcock, 1894 by K. Baba) from Philippine waters. Shiino (1958) described Pseudione lenticeps infesting Munida japonica heteracantha Ortmann, 1892 (now M. heteracantha ) from Japanese waters. Boyko (2004), after examination of numerous specimens from Taiwan and the Philippines, determined that P. lenticeps was a junior synonym of P. retrorsa and transferred Pseudione retrorsa to Aporobopyrus . The present specimens ( Figures 2 , 3 ) also come from Philippine waters and this is the first record of the host species bearing this or any parasitic isopod. Pseudione retrorsa is now known from seven different host squat lobsters, all in Munididae (see Boyko et al. 2012).

Philippine specimens have both dextral ( Figure 2 ) and sinistral ( Figure 3 ) forms, and show some characters that are different from those reported by Richardson (1910) and Boyko (2004). The present females have antennae and antennules of three and five articles, respectively ( Figures 2C , 3C ). Boyko (2004) reported antennae and antennules of three articles each while Richardson (1910) described the first pair of antennae with four articles and the second pair (antennules) with five articles. However, re-examination of the female syntype (USNM 40925) by one of us (CBB) shows that the antennules actually have four articles, not five. Richardson (1910) did not give any description of the maxilliped or oostegite 1. Boyko (2004) reported the maxilliped with a short subacute spur, lacking a palp, with the distolateral margin irregular and crenulated and the internal ridge of oostegite 1 with one large smooth lobe. The present specimens show the maxilliped with a reduced palp ( Figures 2E, F , 3E ), and the internal ridge of oostegite 1 with small tubercules ( Figures 2H , 3G ). Despite these differences, from the overall body shape and others from diagnostic characters, the present specimens fall within the range of variability reported for this species.

Figures

Figure 2. Aporobopyrus retrorsa (Richardson, 1910) (CI1081y). Female, 8.58 mm (A–J): (A) dorsal view; (B) ventral view; (C) left antenna and antennule; (D) right side of barbula;; (E) right maxilliped, external view; (F) palp of maxilliped; (G) right oostegite 1, external view; (H) right oostegite 1, internal view; (I) right pereopod 1; (J) right pereopod 7. Male, 3.33 mm (K– Q): (K) dorsal view; (L) ventral view; (M) right antenna and antennule; (N) left pereopod 1; (O) right pereopod 2; (P) right pereopod 3; (Q) right pereopod 7. Scale bars = 1 mm (A, B), 0.14 mm (C, F, M–Q), 0.18 mm (D), 0.40 mm (E, G, H), 0.15 mm (I, J), 0.38 mm (K, L).

Figure 3. Aporobopyrus retrorsa (Richardson, 1910) (CI1081z). Female, 6.97 mm (A–J): (A) dorsal view; (B) ventral view; (C) right antenna and antennule; (D) barbula; (E) right maxilliped, external view; (F) right oostegite 1, external view; (G) right oostegite 1, internal view; (H) right pereopod 1; (I) right pereopod 7; (J) left pleopods 1, 2. Male, 3.14 mm (K–S): (K) dorsal view; (L) ventral view; (M) male, 3.25 mm, dorsal view; (N) right antenna and antennule; (O) ventral view of pleon; (P) left pereopod 1; (Q) right pereopod 2; (R) right pereopod 3; (S) right pereopod 4. Scale bars = 1 mm (A, B), 0.22 mm (C, H, I, N), 0.56 mm (D), 0.60 mm (E–G, J), 0.64 mm (K–M), 0.47 mm (O), 0.20 mm (P–S).