Cancricepon beibusinus, An & Wang & Boyko & Williams, 2019

An, Jianmei, Wang, Mingxiao, Boyko, Christopher B. & Williams, Jason D., 2019, New hosts and localities for species of Cancricepon Giard & Bonnier, 1887 (Isopoda: Epicaridea: Bopyridae) with description of two new species and comments on the relationship between Cancricepon and Trapezicepon Bonnier, 1900, Zootaxa 4559 (1), pp. 136-150 : 144-148

Cancricepon beibusinus n. sp.

( Fig. 5 )

urn:lsid:zoobank.org:act:B6E28ACF-FA65-429A-8944-076E9FA423B4

Cancricepon choprae .— An, 2009: 5 –6, fig. 3.— Yu & An, 2008: 691 [list] (not Cancricepon choprae (Nierstrasz & Brender à Brandis, 1925).

Material examined. Infesting female Scalopidia spinosipes Stimpson, 1858 , mature sinistral female holotype (6.8 mm) (MBMCAS CIEO 625301), mature male allotype (2.5 mm) (MBMCAS CIEO 625302), China, Beibu Gulf, Stn. 6253, 19°00’00”N, 107°30’00”E, 67 m, 10 Feb 1960, coll. Z. Fan; infesting female S. spinosipes , mature sinistral female paratype (5.6 mm) ( MBMCAS CIEO 625601 ), mature male paratype (1.9 mm) ( MBMCAS CIEO 625602 ), China, Beibu Gulf , Stn. 6256, 17°30’00”N, 107°30’00”E, 67.7 m, 13 July 1960, coll. Z. Fan.

Description. Holotype female length 6.8 mm, maximal width 5.0 mm across third pereomere, head length 1.7 mm (include frontal lamina), head width 1.8 mm. All body regions and segments distinct; no pigmentation ( Fig. 5A, B ).

Head subovate, anterior margin bilobate and posteriorly curved; prominent frontal lamina extending beyond both sides of head and frontal margin; eyes lacking. Antennules and antennae of three and four articles each, respectively, distal articles small; setae on most articles ( Fig. 5C ). Maxilliped with large, broad palp, setae on inner margin ( Fig. 5D ). Barbula with two large falcate projections laterally, outer projections larger than inner ones; pair of triangular projections medially ( Fig. 5E ).

Pereon with seven segments, broadest across pereomere 3 ( Fig 5A ); first four pereomeres with round dorsolateral bosses, pereomeres 2 and 3 with tergal projections ( Fig. 5A ). Brood pouch completely covered by oostegites ( Fig. 5B ). Last three pereomeres with middorsal projections, on fifth and sixth pereomeres rounded and directed posteriorly, on seventh pereomere acute and directed anteriorly ( Fig. 5A ). First oostegite ( Fig. 5F, G ) with two articles of approximately equal length, anterior article subovate, posterior article strongly tapered distolaterally, internal ridge with one larger thin projection nearly extending to the posterior margin of posterior article, several smaller subacute projections medially. Pereopods subequal in structure, propodus small, posterior pereopods larger ( Fig. 5H, I ).

Pleon of six pleomeres, first two and last two with smooth dorsal surfaces, pereomeres 3, 4 medially indented and bilobed. First five pleomeres with uniramous lateral plates and biramous pleopods; lateral plates and pleopods with densely digitate margins and surfaces with small tubercules ( Fig. 5A, B, J ); endopodites smaller than associated exopodites ( Fig. 5J ). Sixth pleomere with uniramous uropods, similar in structure to exopodite of pleopod 5 ( Fig. 5A ).

Allotype male length 2.5 mm, maximal width across fourth pereomere 0.9 mm, head length 0.2 mm, head width 0.4 mm ( Fig. 5K, L ).

Head an oblong ellipse, anterior and posterior margins rounded, minute dark eyes near posterior edge ( Fig. 5K ); head and first pereomere separated ( Fig. 5K ). Antennules with three articles each, distal two articles with setae; antennae with four articles each, distal three articles covered with setae ( Fig. 5M ).

Pereon of seven segments, fourth pereomere widest. All pereomeres with round midventral tubercles ( Fig. 5L ). Pereopods subequal in structure, median three pairs slightly larger than others. Carpi, meri and propodi of pereopods with scales on ventral surfaces ( Fig. 5N ).

Pleon of six segments, without midventral tubercles. First five pleomeres with lateral tuberculate pleopods ( Fig. 5L ), sixth pleomere (pleotelson) with truncate posterior margin, lacking uropods or posterolateral lobes ( Fig. 5L ).

Etymology. The species name is derived from the type locality, the Beibu Gulf, whose name in Chinese is Běibù Wān or "Northern Bay" of the South China Sea.

1 Bourdon (1971) gave Côte d’Ivoire and Dahomey (= Benin) as the type locality for C. anagibbosus in different parts of the paper; Côte d’Ivoire is the correct type locality, based on the data labels associated with the type specimens (MNHN-IU-2007-3702, MNHN-IU-2007-3703).

2 Markham’s (1979) Bermuda record is highly speculative as he reported only a single specimen of P. herbstii with an empty branchial swelling.

3 Eriphia gonagra as a host for C. choprae is highly speculative; Hay & Shore identified a parasite in this host as Leidya distorta (Leidy, 1855) , but although that identification is probably incorrect, based on other hosts known for that species, the true identity of the parasite is not known (see Hay and Short 1918; Markham 1975).

4 The identity of this specimen is not verified as even belonging to a species of Cancricepon ; the host has otherwise never been reported bearing bopyrids.

5 Dyspanopeus sayi & D. acanthophora are both listed as hosts for C. choprae in Markham, 1979 but without any information as to where they were collected. They were not from Bermuda, which was the locality of focus in Markham (1979) and were only included in a long list of hosts from the total range of C. choprae known at that time (“Carolinas through Florida to Mississippi; Vera Cruz, Mexico; Curaçao ”).

6 No morphological details or illustrations were given and it is unknown if this specimen belongs to Cancricepon .

Remarks. The type specimens of this species were originally identified as C. choprae , despite the enormous geographical distance separating them from any previously identified specimens of that species in the western Atlantic. The Chinese specimens can be separated from C. choprae by several characters of the females, including head with frontal lamina extending posteriorly on the sides of the head approximately half way (extending nearly to the posterior margin of the head in C. choprae ), pereomeres 2 and 3 with completely to partly distinct median region (no regional separation in C. choprae ), seventh pereomere middorsal projection acute (rounded in C. choprae ), and first oostegite internal ridge with numerous tapered projections (few low rounded projections in C. choprae ). Males of the two species can also be separated in that those of C. beibusinus n. sp. have a truncate pleotelson that lacks posterolateral lobes and a prominent anal cone (lobes and anal cone present in C. choprae ); additionally, it appears that the number of pleonal midventral tubercles is different between the species, as there are none in C. beibusinus n. sp., but Markham’s (1975) illustration of a male C. choprae shows what appears to be midventral tubercles on pleomeres 1–3, although these were not mentioned in his text. This new species can also be separated from all other species in the genus by the characters given in the key below.

Figures

FIGURE 5. Cancricepon beibusinus n. sp., holotype female (MBMCAS CIEO 625301) (A–J), allotype male (MBMCAS CIEO 625302) (K–N): A, dorsal view; B, ventral view; C, right antennule and antenna; D, right maxilliped, external view; E, barbula; F, right oostegite 1, external view; G, right oostegite 1, internal view; H, right pereopod 2; I, right pereopod 7; J, right pleopod 1; K, dorsal view; L, ventral view; M, left antennule and antenna; N, left pereopod 1. Scale bars: A, B, K, L = 1 mm; C = 220 µm; D = 410 µm; E = 550 µm; F, G, J = 730 µm; H, I = 280 µm; M, N = 125µm.