Ithyleucon sorbei, Corbera, Jordi, 2012

Corbera, Jordi, 2012, Rare and new cumaceans (Crustacea, Peracarida) from the southern margin of the Cap Ferret Canyon (Bay of Biscay), ZooKeys 235, pp. 73-85 : 77-81

Ithyleucon sorbei sp. n. Figs 24

Pseudoleucon sp. A - Elizalde et al. 1993, p. 253.

Material examined.

Holotype: Cap Ferret Canyon, Bay of Biscay, ESSAIS II, stn TS13, 44°34.19'N, 2°16.18'W, 1097-1099 m, 17/05/89, preadult female (ICMU12101901), Jean-Claude Sorbe leg.

Paratypes: Same data as the holotype, 1 preadult female (ICMU12101903), 1 preadult female dissected in two slides (ICMU12101902), 2 preadult males (ICMU12101904 and ICMU12101905); ESSAIS I, stn TS12, 44°32.30'N, 2°15.10'W, 1024-1043 m, 22/04/89 1 immature male (ICMU12101906), Jean-Claude Sorbe leg.

Diagnosis.

Carapace without ridges, frontal lobe with two teeth and others located posteriorly. Pseudorostral lobes extending anterodorsally, upturned, anterior margin serrate. Antenna 1 geniculate between peduncle articles 1 and 2, accessory flagellum extending beyond the mid-length of main flagellum. Female with exopods on pereopods 1-3; male with exopods on pereopods 1-4. Uropod peduncle shorter than rami; endopod bi-articulate, slightly shorter than exopod. Male with 2 pairs of pleopods.

Description.

Preadult female 3.125 mm total length. Carapace (Fig. 2) slightly longer than a fourth of the total length; frontal lobe with two teeth and others (3-4) positioned posteriorly on the middorsal line. Pseudorostral lobes extending anterodorsally, upturned by an angle of about 90°, anterior margin serrate; antennal notch small, anterolateral angle acute with 0-3 serrations on the lower margin

Antennula (Fig. 3A), peduncle 3-articulate, geniculate between articles 1 and 2; article 1 longer than the combined lengths of articles 2 and 3; article 2 shorter than article 3; main flagellum 3-articulate, shorter than the last peduncle article, with two aesthetascs and three long simple setae terminally; accessory flagellum longer than the main flagellum of article 1, with three long simple setae positioned terminally.

Antenna 2 (Fig. 3B) 3-articulate, with two pappose setae on article 1.

Mandible (Fig. 3C) base truncate, lacina mobilis with three teeth, two simple setae between lacina mobilis and pars molaris.

Maxillula (Fig. 3D) inner endite with five setae, one simple, three pappose and one bifid; outer endite with cuspidate setae.

Maxilla (Fig. 3E) with 3 endites; broad endite with 5 simple and several pappose setae terminally; narrow endites not extending beyond the distal margin of broad endite; inner narrow endite with 5 simple setae terminally; outer narrow endite with 4 simple setae terminally.

Maxilliped 1 (Fig. 3F) reduced with only three articles, dactylus minute.

Maxilliped 2 (Fig. 3G) basis shorter than rest of appendage, with a pappose seta on distal inner corner; merus with a long seta; carpus longer than merus with several simple setae on inner margin; propodus shorter than carpus, with a pappose seta on distal outer corner and several setae on inner margin; dactylus with two simple setae terminally.

Maxilliped 3 (Fig. 4A) with well developed exopod, basis longer than rest of appendage, produced distally, with three long pappose setae on distal outer corner and three pappose setae on inner margin; merus with small pappose sete on inner margin and a long pappose seta on distal outer corner; carpus as long as merus, with pappose seta on inner margin and two simple setae on distal outer corner; propodus shorter than carpus with a pappose seta on inner margin; dactylus shorter than propodus.

Pereopod 1 (Fig. 4B) with well developed exopod, basis shorter than the following three articles combined, with three pappose setae on its inner margin and a longer one on distal corner; ischium with a small simple seta on inner margin; merus half the length of carpus, with small pappose setae; carpus as long as propodus, with short simple setae on both margins and four long simple setae distally; propodus with simple setae on both margins; dactylus shorter than propodus, with five long simple setae terminally and some smaller ones along the margins.

Pereopod 2 (Fig. 4C) with well-developed exopod, basis as long as rest of appendage, with three pappose setae on inner margin and a long one on distal outer corner; ischium very short; as long as carpus; carpus with simple setae on distal margin; propodus half length of dactylus; dactylus with a simple setae on each margin and four terminally (the longest longer than the article).

Pereopod 3 (Fig. 4D) with well-developed exopod, basis longer than the rest of appendage, with a simple seta on distal anterior corner; ischium with three simple and a pappose setae on distal corner; merus twice as long as ischium, with a simple seta on distal corner; carpus twice as long as merus, with two long simple setae (distally annulated) on distal corner; propodus longer than half length of carpus with a long simple seta (distally annulated) on distal corner.

Pereopod 4 (Fig. 4E) basis as long as the rest of appendage, with simple and pappose setae on both margins; ischium with two long simple setae; merus with a simple seta on distal corner; carpus 1.5 times as long as merus, with two simple seta on the margin and two (distally annulated) on distal corner; propodus as long as merus, with a long simple seta (distally annulated) on distal corner.

Pereopod 5 (Fig. 4F), basis as long as the three following article combined length; carpus twice as long as merus, with two simple setae (distally annulated) on distal corner; propodus as long as merus, with a long simple seta (distally annulated) on distal corner.

Uropod peduncle (Fig. 4G) slightly longer than the last pleonite and 0.66 times as long as exopod, with five small cuspidate setae on inner margin. Endopod 2-articulate; article 1, 1.6 times as long as article 2, with 10 cuspidate setae on inner margin; article 2 with six cuspidate setae on inner margin and one terminally. Exopod 2-articulate, slightly longer than endopod; article 2 with simple setae on the outer margin and upper face, five pappose setae on inner margin, and two long simple setae terminally.

Preadult male 3.63 mm total length (Fig. 2B). Similar in most characteristics-apart from the sexual ones-to the female but with a shorter pseudorostrum, a lower number of teeth on the middorsal line and without antennal notch. However, the pseudorostrum of the immature male (pleopods reduced to a single bud with few terminal simple setae) is long as it is in females (Fig. 2C).

Etymology.

The new species is named in honour of Jean-Claude Sorbe (Arcachon, France) in recognition of his extensive work studying suprabenthic communities.

Distribution.

Bay of Biscay, N Atlantic between 1024 and 1099 m depth.