“Mothocya omidaptria sp. nov.
Material. All specimens from Hyporhamphus unifasciatus, f~ (ovig. 18.2mm), HOLOTYPE USNM 216363; ~ (orig. 16"2ram, no. 18), USNM 216365; ~ (non-orig. 16.8mm, no. 14), USNM 216365; ~2 (non-ovig. 14-2ram, no. 16), MCZ uncat; ~ (preorig. 16.0ram), ~ (9.5mm, no. 17); d ~ (c. 9.1 mm), USNM 216364; ~ (9.1 ram, no. 26), USNM 216365; ~ (broken in two), USNM 216365; all Rio de Janeiro, Brazil; only data is Thayer-Agassiz, 1865. Two ~ (ovig. 14-9, non-ovig. 15.0ram), 4 ~ (7-5, 7-8, 7-8, 8.4mm), Curaqao, West Indies, 10-18.ii.1884, coll. US Fisheries Albatross (USNM 216366).
Types. HOLOTYPE, USNM 216363; PARATVPES, USNM 216364, 216365, MCZ uncatalogued.
Type-locality. Rio de Janeiro, Brazil, 22°53'S, 43°1TW.
Description of female. Body 2-13-2.30 times longer than wide, weakly to moderately twisted to one side, widest at pereonite 5. Rostrum strongly produced, apex narrow, scarcely turned down; eyes moderate, facets indistinct, about 0.54 times width of cephalon. Coxae all narrow, those of pereonites 6 and 7 extending beyond posterior of segment, those of pereonite 7 with posterolateral corner acute or subactue; lateral margins of most coxae weakly to moderately concave. Posterior margin of pereonite 7 strongly recessed. All pleonites at least partly visible in dorsal view, lateral margins extending beyond coxal plate of pereonite 7 one one side; pleon 0.90-1.01 times width of pereonite 5. Pleotelson 0.67-0.72 times longer than wide, widest at about midlength, posterior margin evenly rounded. Antennule composed of eight articles. Antenna composed of eight articles, first two of which are short and broad, remaining articles slender. Mandible palp robust, not extending beyond apex of incisor. Maxillule with one broad-based and three slender spines. Maxilla with two spines on medial lobe, three on lateral lobe. Maxilliped article 3 slender, with three terminal hooked spines and fourth hooked spine on proximomedial margin. Pereopods robust, pereopod 7 substantially larger than pereopod 1. Brood pouch with anterior pair of oostegites, smallest; deepest midlength to posterior. Pleopod 1 peduncle lateral lobe barely developed, those of pleopods 2 to 5 moderately developed. Proximomedial lobe of
endopods 3 to 5 feebly developed, that of pleopod 5 slightly larger than that of pleopod 4. Uropod rami extending beyond posterior margin of pleotelson, apices of both rami narrow, subacute; endopod margins straight, converging rapidly to apex; Exopod slightly sinuate, margins converging distally.
Male. Antennule similar to that of female, antenna with nine articles, first two not noticably broader. Maxilla lateral lobe with two spines. Maxilliped article 3 with three hooked spines. Penes set close, but not adjacent to each other. All males with damaged pleopods; proximomedial lobe on endopods 3 to 5 large, that of pleopod 5 conspicuously larger than that of pleopod 4. Uropod longer than in female, otherwise similar.
Colour. Pale tan in alcohol, females without conspicuous chromatophores on dorsal surface; males with chromatophores on dorsal surface and appendages.
Size. Ovigerous females 16.2-18.2 mm, non-ovigerous females 14.2-16.8 mm; males 9.1-9.5mm.
Variation. The degree to which the posterior coxae are produced varies, as does the relative width of the uropodai endopod. The uropod exopod of some specimens is very nearly straight, in others it is weakly sinuate. Males and immature females have only two spines on the lateral lobe of the maxilla. The specimens from Curacao have larger proximomedial lobes on the endopods of pleopods 3 to 5 than do specimens from Brazil.
Remarks. The most useful characters to identify this species are the narrowly produced rostrum, the acute coxae of pereonite 7, the pleon extending laterally beyond the coxae of pereonite 7 one one side, and relatively long uropodal rami with a narrow endopod and sinuate exopod.
Mothocya nana is separated by having the anterior margin of the rostrum truncate, shorter coxae, those of pereonite 7 with blunt posterior margins, and larger proximomedial lobes on the endopods of pleopods 3 to 5.
Hosts. Known only from Hyporhamphus unifasciatus.
Distribution. Known only from Rio de Janeiro, Brazil, and Curacao, West Indies
Etymology. The epithet is derived from the Greek words omis (one of the many for fish) and daptria (eater).”
(Bruce, 1986: 1127-1129)
