Cyclaspis hyalinus, Jarquín-González, Jani & García-Madrigal, María Del Socorro, 2013

Jarquín-González, Jani & García-Madrigal, María Del Socorro, 2013, Annotated checklist and keys for cumaceans (Crustacea: Peracarida) from the Tropical Eastern Pacific, with six new species from the Southern Mexican Pacific, Zootaxa 3721 (3), pp. 201-257 : 219-224

Cyclaspis hyalinus sp. nov.

Figs 10–13

Type material. Holotype female, UMAR-Pera 488, Copalita mouth river, Huatulco, Oaxaca, dredging, depth 10 m, sandy sediment, 7 May 2007. Paratypes, 2 males (one dissected), 1 ovigerous female (dissected), 2 females, 1 juvenile, UMAR-Pera 489, same locality and date.

Diagnosis. Both sexes with integument of the body finely setose; carapace with smooth middorsal line. Female. Maxilliped 3 with five pappose setae on basis expansion; pereopod 1 with 18 setulate setae on the inner margin; endopod of the uropod with apical seta fused. Male. Maxilliped 3 with six pappose setae on basis expansion; pereopod 1 with 16 setulate setae and four cuspidate setae on the inner margin.

Description. Ovigerous female, 2.5 mm ( Figs 10 A–B). Body translucent and integument of the body finely setose; carapace oviform and smooth middorsal line; frontal lobe approximately a fourth of the length of the carapace; pseudorostral lobes meet in front of the ocular lobe; ocular lobe pigmented; siphons short; with small antennal notch.

Antenna 1 ( Fig. 10 C) first basal article as long as other articles together; main flagellum uniarticulate; accessory flagellum reduced. Maxilliped 2 ( Fig. 10 D) basis with many distal fine hairlike setae on dorsal surface and two pappose setae; ischium short; merus shorter than carpus; carpus broader than propodus; dactylus about a half propodus; palp with seven annulate setae. Maxilliped 3 ( Fig. 10 E) basis geniculated, with serrate hyaline lamella on the inner margin, expansion of the basis with five pappose setae; merus broad, expansion of the merus with a row of fine hairlike setae on the outer margin and an apical pappose seta; propodus broader than dactylus; dactylus with six setae terminally.

Pereopod 1 ( Fig. 10 F) basis with 18 setulate setulae on the inner margin; merus longer than carpus; carpus shorter than propodus; propodus broader than dactylus; exopod biarticulate with distal article longer than basal article. Pereopod 2 ( Fig. 11 A) basis shorter than the next articles together; merus two times longer than wide; propodus about a third of the length of the dactylus. Pereopod 3 ( Fig. 11 B) similar to the pereopod 2, but merus slightly longer than carpus. Pereopod 4 ( Fig. 11 C) basis truncate; merus and carpus of similar proportions; propodus shorter than dactylus; dactylus pointed. Pereopod 5 ( Fig. 11 D) basis shorter than the rest of the articles; merus longer than carpus; propodus shorter than dactylus; dactylus pointed.

Uropod ( Fig. 11 E) peduncle longer than rami, with some fine hairlike setae on dorsal surface; endopod (excluding the terminal seta) shorter than exopod and uniarticulate, with a setulated seta on the inner margin, apical seta fused; exopod biarticulate, with two distal cuspidate setae on the inner margin and three terminal cuspidate setae.

Adult male, 2.1 mm until third pleonite (Figs 12A–B). The overall appearance resembles the female. Frontal lobe approximately a third of the length of the carapace; pseudorostral lobes with three lenses and little pigment. Second, third and fourth pereonites with a pair of small plumose setae on each lateral margin; fifth pereonite with a pair of small plumose setae on each dorso-distal margin. Abdomen partially lost, includes only the first three segments with their respective pairs of pleopods. Pleotelson and uropods lost.

Antenna 1 (Fig. 12C) with many fine hairlike setae on dorsal surface of the first basal article; main flagellum biarticulate, basal article longer than the distal article; accessory flagellum small and uniarticulate. Antenna 2 (Fig. 12D) with at least four basal articles, fourth article longest; flagellum with short articles. Maxillule (Fig. 12E) with two endites, outer endite with 11 cuspidate setae; inner endite with five setae. Maxilla (Fig. 12F) broad endite with 17 setae on the inner margin; distal narrow endite with eight distal setae. Maxilliped 2 (Fig. 12G) basis with two distal plumose setae on dorsal surface; dactylus with a cuspidate seta. Maxilliped 3 (Fig. 12H) basis straight, longer than the rest of the articles together, with a row of fine hairlike setae on the inner margin; expansion of the basis with six pappose setae; merus with distal hyaline lamellae produced reaching beyond the end of the carpus; carpus slightly longer than propodus; dactylus lost.

Pereopod 1 ( Fig. 13 A) basis with four cuspidate setae and 16 setulate setae on the inner margin; merus and carpus of the same length; dactylus longer than wide, with six setae; exopod with distal article shorter than basal article. Pereopod 2 ( Fig. 13 B) basis with six plumo-annulate setae on dorsal surface; merus about three times longer than wide. Pereopod 3 ( Fig. 13 C) similar to the female. Pereopod 4 ( Fig. 13 D) basis shorter than the rest of the articles together; merus shorter than carpus. Pereopod 5 ( Fig. 13 E) merus shorter than carpus. Pleopod 2 ( Fig. 13 F) peduncle longer than rami, with five plumose setae on the inner margin; endopod biarticulate.

Etymology. The species name is derived from the latin hyalinus , referring to the transparent or translucent body.

Remarks. About 140 species of Cyclaspis have been described around the world; however, females of Cyclaspis hyalinus clearly differ from females of all other Cyclaspis species by the conformation of the main flagellum of the antenna 1, maxilliped 3 and the shape of the uropod. We only compare the females of the new species with females of other species of Cyclaspis known from the Eastern Pacific.

According to Donath-Hernández (2011b), nine species of Cyclaspis are known from the west coast of America: Cyclaspis nubila Zimmer, 1936 (Corona del Mar, California), C. giveni Donath-Hernández, 2011 b (Todos Santos Bay, Baja California), C. concepcionensis Donath-Hernández, 1988 (Concepcion Bay, Baja California), C. bituberculata Donath-Hernández, 1988 (Bacochibampo Bay, Sonora), C. dolera Zimmer, 1944 (Salinas Bay, Costa Rica), C. breedyae Petrescu & Heard, 2004 (Gulf of Nicoya, Costa Rica), C. vargasae Petrescu & Heard, 2004 (Murcielago Island, Costa Rica), C. testudinum Zimmer, 1943 a, (Chatam Island, Galapagos), and C. peruana Zimmer, 1943 a (Independencia Bay, Peru).

However, contrasting with the other species mentioned in this work, C. hyalinus is completely different from any other species of Cyclaspis previously reported in the Eastern Pacific for the conformation of the uropods and antenna 1 principally; the closest species is C. nubila and they differ in females because C. hyalinus has the antenna 1 with uniarticulate main flagellum, whereas C. nubila has the flagellum biarticulate; C. hyalinus has the endopod of the uropod with apical seta fused, whereas in C. nubila is not fused; C. hyalinus has two cuspidate setae on the inner margin of the endopod of the uropod, while C. nubila has nine cuspidate setae. Cyclaspis hyalinus differs from female of C. boquillenses because C. hyalinus has a smooth middorsal line on carapace, whereas C. boquillensis has three teeth; C. hyalinus has a row of fine hairlike setae on the outer margin of the merus expansion of the maxilliped 3, while C. boquillensis has a cuspidate seta ( Table 2 ).

Figures

FIGURE 10. Cyclaspis hyalinus, Paratype ovigerous female, 2.5 mm, UMAR-Pera 489, Copalita mouth river, Huatulco, Oaxaca: A) habitus dorsal view; B) habitus lateral view; C) antenna 1; D) maxilliped 2; E) maxilliped 3; F) pereopod 1.

FIGURE 11. Cyclaspis hyalinus, Paratype ovigerous female, 2.5 mm, UMAR-Pera 489, Copalita mouth river, Huatulco, Oaxaca: A) pereopod 2; B) pereopod 3; C) pereopod 4; D) pereopod 5; E) uropod.

FIGURE 13. Cyclaspis hyalinus, Paratype male, 2.1 mm, UMAR-Pera 489, Copalita mouth river, Huatulco, Oaxaca: A) pereopod 1; B) pereopod 2; C) pereopod 3; D) pereopod 4; E) pereopod 5; F) pleopod 2.