Parapenaeon diatropa, An & Markham & Li, 2015

An, Jianmei, Markham, John C. & Li, Xinzheng, 2015, A review of the genus Parapenaeon Richardson, 1904 (Crustacea: Isopoda: Bopyridae: Orbioninae), with description of three new species from China, Journal of Natural History 49 (41), pp. 2527-2557 : 2545-2548

Parapenaeon diatropa sp. nov.

( Figures 7 , 8 )

Material examined

Infesting Metapenaeopsis dalei (Rathbun) , Det. of host, Xinzheng Li. Holotype: CIEPE001101-1 , ♀ , allotype, CIEPE001101-2 , ♂, East China Sea, Stn. H 6, 28° 10 ′ N, 122°45 ′ E, 78 m, 25 November 2000 . Paratype: CIEPE601102 , 2♀♀, 2♂♂, South China Sea, Stn. 6011, 22°45 ′ N, 117°00 ′ E, 38 m, 24 April 1960, coll. Mu Chen. Other materials: CIEPE001102 , 2♀♀, 2♂♂, East China Sea, Stn. G 4, 29°45 ′ N, 124° 00 ′ E, 60 m, 23 November 2000, coll. Lusan Liu. CIEPE601103 , 2♀♀, 2♂♂, South China Sea, Stn. 6011, 22°45 ′ N, 117°00 ′ E, 38 m, 24 April 1960, coll. Mu Chen. CIEPE601104 , 2♀♀, 2♂♂, South China Sea, Stn. 6011, 22°45 ′ N, 117°00 ′ E, 38 m, 24 April 1960, coll. Mu Chen. CIEPE601105 , 2♀♀, 2♂♂, South China Sea, Stn. 6011, 22°45 ′ N, 117°00 ′ E, 38 m, 24 April 1960, coll. Mu Chen. CIEPE601106 , 2♀♀, 2♂♂, South China Sea, Stn. 6011, 22°45 ′ N, 117°00 ′ E, 38 m, 24 April 1960, coll. Mu Chen. CIEPE413406 , ♀, ♂, East China Sea, Stn. 4134, 29°30 ′ N, 123°00 ′ E, 61 m, 17 April 1959, coll. Leren Chen. CIEPE601107 , 2♀♀, 2♂♂, South China Sea, Stn. 6011, 22° 45 ′ N, 117°00 ′ E, 38 m, 24 April 1960, coll. Mu Chen. CIEPE601108 , ♀, ♂, South China Sea, Stn. 6011, 22°45 ′ N, 117°00 ′ E, 38 m, 24 April 1960, coll. Mu Chen. CIEPE601109 , 2♀♀, 2♂♂, South China Sea, Stn. 6011, 22°45 ′ N, 117°00 ′ E, 38 m, 24 April 1960, coll. Mu Chen. CIEPE601110 , 2♀♀, 2♂♂, South China Sea, Stn. 6011, 22°45 ′ N, 117°00 ′ E, 38 m, 24 April 1960, coll. Mu Chen. CIEPE601111 , 2♀♀, 2♂♂, South China Sea, Stn. 6011, 22°45 ′ N, 117°00 ′ E, 38 m, 24 April 1960, coll. Mu Chen. CIEPE001102 , 17♀♀, 15♂♂, East China Sea, Stn. H 6, 28°10 ′ N, 122°45 ′ E, 78 m, 25 November 2000 . CIEPE601112 , 3♀♀, 2♂♂, South China Sea, Stn. 6011, 22°45 ′ N, 117°00 ′ E, 38 m, 24 April 1960, coll. Mu Chen. CIEPE000101 , 9♀♀, 5♂♂, East China Sea, Stn. G 4, 29°45 ′ N, 124°00 ′ E, 60 m, 23 January 2000, coll. Lusan Liu. CIEPE001103 , 9♀♀, 7♂♂, East China Sea, Stn. H 6, 28°10 ′ N, 122°45 ′ E, 78 m, 25 November 2000 . CIEPE000102 , 16♀♀, 12♂♂, East China Sea, Stn. G 4, 29°45 ′ N, 124°00 ′ E, 60 m, 23 January 2000, coll. Lusan Liu. CIEPE000103 , 11♀♀, 13♂♂, East China Sea, Stn. G 4, 29°45 ′ N, 124°00 ′ E, 60 m, 23 January 2000, coll. Lusan Liu.

Description of holotype female (CIEPE001101-1) ( Figure 7 A-I)

Length 5.97 mm, maximal width 4.09 mm, head length 0.94 mm, head width 1.24 mm.

Head oval, with deep bilobate anterior edge and curved posterior edge, welldeveloped frontal lamina extending beyond sides of the head ( Figure 7A ). Eyes absent. First and second antennae of three and five articles, respectively, terminal setae not evident ( Figure 7C ). Maxilliped triangular, with short curved stout palp ( Figure 7D ). Barbula with two pairs of lateral projections on each side, outer pair with slightly digitate edge, but inner projections smooth. ( Figure 7E ).

Pereon broadest across fourth pereomere ( Figure 7A ). Coxal plates welldeveloped on long side of all pereomeres, margins entire. Coxal plates on short side of first two pereomeres also well-developed, but those on other pereomeres rudimentary. Dorsolateral bosses on first five pereomeres. Brood pouch wide open ( Figure 7B ). First oostegite ( Figure 7F, G ) plates of nearly equal length, internal ridge bearing five to eight small tubercules, posterolateral point broadly triangular, pointing posteriorly, and with posterior edge curved. Pereopods larger posterior ( Figure 7H, I ), surface of the carpi and meri smooth, bases of all pereopods produced into lobes.

Pleon of six pleomeres, first five bearing tubercular biramous pleopods and rudimentary lateral plates. Pleopods are slender and do not extend beyond edges of lateral plates, so they are not visible in dorsal view ( Figure 7B ). Fifth pleomere widely median separated, and small sixth pleomeres can be seen from dorsal view ( Figure 7A ). Biramous uropods tuberculate. Exopodites of uropods different endopodites, the former larger, sharp terminal, and slender, but the latter short, cylindrical. Uropods are visible dorsally ( Figure 7B ).

Description of allotype male (CIEPE001101-2) ( Figures 7J, K , 8 )

Length 1.99 mm, maximal width across pereonite 5, 0.83 mm, head width 0.50 mm, pleonal length 0.42 mm. All pereomeres distinct, pleon fused ( Figures 7J, K , 8 ).

Head ( Figure 7J ) trapezoidal, its posterior edge straight. Black eyes near posterolateral corners of head ( Figure 7J ). First and second antennae ( Figure 8A ) of three and four articles respectively, setae not evident.

Pereomeres almost equally wide, lacking midventral projections ( Figures 7J , 8A ). Pereomeres 2 and 4 with pigment on surface ( Figure 7J ). First three pereopods ( Figure 8B ) with longer dactyli and smaller carpi than last four pereopods ( Figure 8C ). All propodi, carpi and meri with setae on their ventral surface ( Figure 8B, C ).

Pleon fused, median part with pigment. Anal cone visible in dorsal view ( Figure 7K ).

Variations

Immature females have black eyes, flatter bodies and coxal plates on the short sides of all pereomeres; other characters agree with the holotype.

Etymology

The specific name, the Greek adjective diatropos, refers to uropods of holotype female with remarkable diverse rami.

Remarks

The new species, P. diatropa , is most similar to P. japonica ( Thielemann 1910) . The female of P. diatropa differs from that of P. japonica in longer body shape, uropods with remarkable different rami, cylindrical endopodite and longer and sharp exopodite; pleopods not extending beyond the margin of pleon, cannot be seen from the dorsal view; a simple barbula whose inner projections are almost smooth, oostegite 1 with almost smooth inner ridge bearing only small tubercules, whereas in P. japonica , almost round body shape, flake shape uropods with similar endopodite and exopodite; pleopods usually extending beyond the margin of pleon; heavy tubercular digitate projections on each side of the barbula; having long and thick tubercules on the inner ridge of oostegite 1.

Figures

Figure 7. Parapenaeon diatropa sp. nov. Holotype female (CIEPE001101-1) (A–I). (A) Dorsal view; (B) ventral view; (C) left antennae; (D) left maxilliped, external view; (E) left side of the barbula; (F) left oostegite 1, external view; (G) left oostegite 1, internal view; (H) right pereopod 1; (I) right pereopod 7. Allotype male (CIEPE001101-2) (J, K). (J) Dorsal view; (K) ventral view. Scale bars: A, B, 1 mm; C, H, I, 0.26 mm; D–G, 0.42 mm; J, K, 0.43 mm.

Figure 8. Parapenaeon diatropa sp. nov. Scanning electron micrographs of another male (CIEPE601103) (A–C). (A) Ventral view of the male; (B) right pereopods 1 and 2. (C) Right pereopods 6 and 7. Scale bars: A, 1 mm; B, C, 100 µm.