Hyperoche picta Bovallius 1889

Hyperoche picta Bovallius, 1889

(Figs. 6–7)

Hyperoche picta Bovallius, 1889: 111 –115, pl. 7, figs. 32–35.— Senna 1908: 168 –173, text figs. 11–20. Stephensen 1924: 79 –80. Stephensen 1925: 229 (table). Pirlot 1929: 118. Barnard 1930: 415 (key). Thurston 1976: 386 & 387 (table), 415. Harbison et al. 1978: 251 (table). Laval 1980: 18 (table). Brusca 1981: 10 (list), 41, fig. 7e. Vinogradov et al. 1982: 282 (key), 287–288, fig. 146. Lin et al. 1995: 122 (table). Lin et al. 1996: 229 (table). Vinogradov & Semenova 1996: 618. Barkhatov et al. 1999: 808 (table). Zelickman 2005: xvi (list). Gasca & Franco-Gordo 2008: 569 (table), 571. Gasca 2009a: 88 (table). Lavaniegos & Hereu 2009: 151 (appendix). Valencia et al. 2013: 51 (table).

Type material. Type material of Hyperoche picta could not be found in the NRS or ZMUC and is considered lost. The type locality is the tropical Atlantic [20°N 39°W], Balder Expedition, 1881.

Diagnosis. Females: Sexually mature at about 3.5–4.0 mm. Antennae 1 shorter than head, about 1.7 x A2. Head length equal to first two pereonites combined. Pereon globular, length about 1.5 x pleon. Gnathopod 1; basis relatively slender, slightly shorter than remaining articles combined; merus without characteristic spoon-shaped projection under carpus; carpal process relatively short, reaching base of dactylus, anterior margin denticulate; posterior and distal margin of propodus also denticulate, forming hood over dactylus medially; dactylus slightly curved, inserted sub-terminally on medial face of propodus in small pocket, length almost 0.4 x propodus. Gnathopod 2 slightly longer and more slender than G1 but similar in structure. Pereopods 3 & 4 similar in length, marginally longer than P5. Pereopod 3; basis length 3.2 x merus; carpus with postero-distal corner produced in slight tooth with denticulate margins, length 1.7 x merus and slightly shorter than propodus; dactylus length almost 0.3 x propodus. Pereopod 4 similar in structure to P3 except the carpus and propodus are slightly more slender. Pereopod 5 is slightly longer than P6; basis length twice merus; carpus length about 1.3 x merus, slightly shorter than propodus; dactylus length almost 0.4 x propodus. Pereopod 6 similar to P5 except for relatively shorter merus; basis length almost 3 x merus. Pereopod 7; coxa fused with pereonite; similar in structure to P6 but slightly shorter. Epimeral plates with postero-distal corner rounded. Uropod 1; peduncle not reaching to limit of peduncle of U2 and to less than half of peduncle of U3; rami of similar length, slightly longer than 0.7 x peduncle. Uropod 2; inner ramus slightly longer than outer, slightly longer than 0.7 x peduncle. Uropod 3; outer ramus similar in width but marginally longer than inner, slightly more than 0.6 x peduncle. Telson triangular, slightly longer than wide, slightly longer than half of peduncle of U3.

Males: Sexually mature at about 4–5 mm. Antennae slightly longer than entire animal. Pereon slender, slightly shorter than pleon. Appendages marginally more slender than in females, otherwise very similar in structure and relative lengths of articles, except for the following minor variations. Gnathopoda with relatively shorter basis and marginally shorter carpal process. Pereopods 6 & 7 with relatively longer merus, similar to P5. Epimeral plates relatively much longer and deeper. Uropod 1 with inner margins of both rami with characteristic proximal excavation. Uropod 3 rami length about 0.7 x peduncle. Telson marginally wider than long, length slightly less than half of peduncle of U3.

Material examined. Three females (ZMUC), eastern Pacific, west of Galapagos Islands [00°18’S 99°07’W], Dana stns. 3558 III, VIII & IX; 2000, 100 & 50 mw respectively, 18 September 1928. One male (ZMUC CRU- 20291), Mediterranean Sea, off Sicily [38°26’N 13°37’E], Thor stn. 730 (Nordboln II), 16 April 1913, (recorded by Stephensen (1924)). Juvenile female (SAMA C7934), off south-eastern Tasmania [44°12.05’S 147°24.43’E], M. Lewis (CSIRO), FRV Southern Surveyor Cruise 492, stn. 81, 15 November 1992.

Remarks. This is one of the smallest but most distinctive species of Hyperoche, reaching sexual maturity at about 3.5–5 mm. It is readily distinguished from all its congeners by the slightly hooded dactyls of the gnathopoda. It is most similar to H. martinezii in the habitus and relative lengths of the antennae of females, and in the relative lengths of the peduncles of the first two uropoda.

The only record of association with gelatinous plankton is with the ctenophore Cestum veneris (Harbison et al. 1978).

Distribution. A relatively rare species tending to inhabit tropical waters. Recorded from the Mediterranean Sea, off Messina and Sicily; the northern Atlantic (20–35°N), and the North Pacific Ocean, in the east from central California to the equator, and in the west from the China Sea region. There is also one record from the central southern Indian Ocean (41°S 58°E; Vinogradov & Semenova 1996). The above record from the Tasman Sea is the first for this region.