Parapenaeonella minutopoda, An & Boyko & Li, 2013

An, Jianmei, Boyko, Christopher B. & Li, Xinzheng, 2013, A review of the genus Parapenaeonella (Isopoda: Bopyridae: Orbioninae), with description of a new species from Chinese waters and synonymy of Parapenaeonella lamellata Bourdon, 1979, Journal of Natural History 47 (41 - 42), pp. 2633-2648 : 2644-2647

Parapenaeonella minutopoda sp. nov.

( Figure 8 )

Parapenaeonella sp. nov. An, 2006: 161–162, fig. 83 [The East China Sea, infesting Atypopenaeus compressipes (Henderson) ]

Material examined

Infesting Atypopenaeus compressipes (Henderson, 1893) . Holotype: CIEPE413301 , ♀, East China Sea, Stn. 4133, 29 ◦ 30 ′ N, 122 ◦ 45 ′ E, 53 m, 10 December 1959, coll., Liren Chen . Allotype: CIEPE413302 , ♂, same data as holotype . Paratypes: CIEPE407401 , ♀, ♂, East China Sea, Stn. 4074, 28 ◦ 30 ′ N, 123 ◦ 00 ′ E, 77 m, 24 October 1959, coll., Liren Chen . Other materials: CIEPE608901 , ♀, ♂, South China Sea, Stn. 6089, 21 ◦ 15 ′ N, 112 ◦ 30 ′ E, 41 m, 7 April 1960, coll., Xuan Zhang . CIEPE408002 , ♀, ♂, East China Sea, Stn. 4080, 28 ◦ 00 ′ N, 122 ◦ 00 ′ E, 52 m, 7 April 1959, coll., Yulin Liao . CIEPE412801 , ♀, ♂, East China Sea, Stn. 4128, 30 ◦ 00 ′ N, 123 ◦ 00 ′ E, 52 m, 25 October 1959, coll., Yuhang Cui . CIEPE408201 , ♀, ♂, East China Sea, Stn. 4082, 28 ◦ 00 ′ N, 123 ◦ 00 ′ E, 80 m, 8 January 1959, coll., Guangyu Lin and Jinzhao Zhu . CIEPE406401 , ♀, ♂, East China Sea, Stn. 4064, 29 ◦ 00 ′ N, 123 ◦ 00 ′ E, 61 m, 22 October 1959, coll., Guangyu Lin . CIEPE751001 , 2♀♀, 2♂♂, East China Sea, Stn. V-3, 27 ◦ 30 ′ N, 122 ◦ 00 ′ E, 75 m, 11 October 1975, coll., Zhichan Tang and Jianshan Xu . CIEPE407402 , ♀, ♂, East China Sea, Stn. 4074, 28 ◦ 30 ′ N, 123 ◦ 00 ′ E, 77 m, 9 December 1959, coll., Yuhang Cui .

Description of holotype (CIEPE413301)

Length 8.43 mm, maximal width 5.13 mm across third pereomere, head length 1.55 mm, head width 1.67 mm, frontal lamina length 0.69 mm ( Figure 8A, B ).

Head oval, anterior margin bilobate, frontal lamina well-developed, extending beyond lateral margins of head. Small eyes in boundary between head and frontal lamina ( Figure 8A ). Antennae and antennules of five and three articles, respectively ( Figure 8C ), setae lacking. Barbula ( Figure 8D ) with one large lateral digitate projection on each side, five to eight tuberculate projections near middle region. Maxilliped ( Figure 8E ) nearly triangular, palp smooth and straight.

Pereon broadest across third pereomere. All pereomeres with lamellar coxal plates tapering to acuminate tips. Dorsolateral bosses on both sides of first four pereomeres ( Figure 8A ). Brood pouch open ( Figure 8B ). First oostegite ( Figure 8F, G ) with narrow and deep groove separating it into two articles externally, internal ridge bearing eight to ten small projections. Posterior margin curved with round and blunt posterolateral point. Pereopods larger posteriorly, each with basis produced into prominent tubercle ( Figure 8H, I ).

Pleon of six pleomeres, first five produced into marginal serrated lateral plates, long and slender with terminal points. Five pairs of biramous pleopods with tuberculate surfaces, much shorter than corresponding lateral plates, not visible from dorsal view ( Figure 8B ). Uniramous uropods with tuberculate surfaces, twice length of fifth pleopod.

Description of allotype male (CIEPE413302)

Length 1.87 mm, maximal width across fifth pereomere, 0.89 mm, head length 0.48 mm, pleonal length 0.46 mm, first pleomeres width 0.62 mm. All pereomere segments distinct ( Figure 8J, K ).

Head an inverted triangle, small eyes near anterior margin. Head and first pereomere distinctly separated ( Figure 8J ). Antennae and antennules of five and three articles, respectively, antennae bearing terminal setae ( Figure 8L ).

Pereon broadest across fifth pereomere, margins of all pereomeres rounded. First five pereopods subequal in shape and size, last two pereopods with longer carpi and slightly shorter dactyli ( Figure 8M, N ).

Pleon fused, first pleomeres visible in dorsal view, others only identifiable from lateral indentations. Midventral tubercle on first pleomere. First five pleomeres with tuberculate uniramous pleopods. Terminal segment curved ventrally, with elongate, uniramous uropods.

Variation

One female (CIEPE408201) has much longer uropods, equal in length to the lateral plates of the fifth pleomere. One female (CIEPE407402) without lateral plates on the first pereomere, possibly due to damage, and some fusion in the median of the pleon. One male (CIEPE407402) with slender filiform pleopods and the midventral tubercle of the first pleomere much larger, somewhat bifurcated, appearing as two tubercles.

Etymology

The specific name, the word minutopoda , refers to the small pleopods of the female that cannot be seen in dorsal view.

Remarks

The present specimens belong to the genus Parapenaeonella by virtue of the welldeveloped lateral plates on all pereomeres of females and the distinct pleopods in males. Females of the new species differ from those of P. distincta in having a widely open brood pouch (completely closed in P. distincta ). Also, females of the new species have small biramous pleopods much shorter than their lateral plates, and these cannot be seen in dorsal view ( P. distincta with larger pleopods extending well beyond their lateral plates, visible in dorsal view). Third, the barbula of the new species is simple, with only one pair of projections (barbula of P. distincta with two pairs of projections). Finally, the male of the new species bears a midventral tubercle on the first pleomere (lacking such a tubercle in P. distincta ).

Figures

Figure 8. Parapenaeonella minutopoda sp. nov. Holotype female (CIEPE413301): (A–I): (A) dorsal view; (B) ventral view; (C) right antenna and antennule; (D) right side of 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. Allotype male (CIEPE413302) (J–N): (J) dorsal view; (K) ventral view; (L) left antenna and antennule; (M) right pereopod 3; (N) right pereopod 5. Scale bars: 1 mm (A, B), 0.19 mm (C), 0.41 mm (D), 0.56 mm (E), 0.51 mm (F, G), 0.26 mm (H, I), 0.23 mm (J, K), 0.22 mm (L), 0.20 mm (M, N).