Elassocumella krakeri sp. nov.

Figs 18–21

Type material. Holotype ovigerous female, UMAR-Pera 503, Mazunte Beach, Tonameca, Oaxaca, 9.14 m, in coral, 11 August 2011. Paratypes, 19 males (one dissected), 62 ovigerous females (one dissected), 31 females, 18 juveniles, UMAR-Pera 504, same locality and date.

Other material examined. 1 juvenile, UMAR-Pera 505, Coral Beach, Ixtapa Island, Guerrero, 1.5 m, coral, 19 September 2007; 1 female, UMAR-Pera 506, Carrizalillo Beach, Puerto Escondido, Oaxaca, depth unknown, bivalve epibiont, 16 August 2006; 11 females, UMAR-Pera 507, Camaron Beach, Zipolite, Oaxaca, littoral, rocks, 12 November 2009; 1 female, 1 juvenile, UMAR-Pera 508, Camaron Beach, Zipolite, Oaxaca, littoral, sand substratum, 12 November 2009; 1 female, UMAR-Pera 509, Camaron Beach, Zipolite, Oaxaca, intertidal, anemones, 20 May 2011; 7 ovigerous females, 3 females, 1 juvenile, UMAR-Pera 510, Panteon Beach, Puerto Angel, Oaxaca, 3 m, coral, 23 March 2007; 2 females, 1 juvenile, UMAR-Pera 511, Estacahuite Beach, Puerto Angel, Oaxaca, 2-3 m, sabellariid colony, 10 September 2005; 1 ovigerous female, 1 female, UMAR-Pera 512, Estacahuite Beach, Puerto Angel, Oaxaca, 2–3 m, algae, 10 September 2005; 11 ovigerous females, 13 females, 15 juveniles, UMAR-Pera 513, Estacahuite Beach, Puerto Angel, Oaxaca, 4 m, coral, 25 August 2006; 8 ovigerous females, 3 females, 1 juvenile, UMAR-Pera 514, Estacahuite Beach, Puerto Angel, Oaxaca, 4 m, coral, 1 December 2006; 1 ovigerous female, UMAR-Pera 515, La Tijera Beach, Pochutla, Oaxaca, 4 m, coral, 30 April 2005; 1 ovigerous female, 1 female, 1 juvenile,UMAR-Pera 516, La Tijera Beach, Pochutla, Oaxaca, 4 m, coral, 12 September 2006; 8 ovigerous females, 11 females, 3 juveniles, 9 juveniles, UMAR-Pera 517, San Agustin Bay, Huatulco, Oaxaca, depth unknown, in coral, 23 February 2010; 1 ovigerous female, UMAR-Pera 518, Maguey Bay, Huatulco, Oaxaca, intertidal, sand substratum, 4 July 2007.

Diagnosis. Male. Lateral margins of the carapace slightly crenulated; exopods on maxilliped 3 and pereopods 1–4; peduncle of the uropod with two distal cuspidate setae on the inner margin. Female. Lateral margins of the carapace with small rounded teeth; peduncle of the uropod with two distal pappose setae on the inner margin.

Description. Adult male, 1.9 mm (Figs 18 A–B). Carapace with long fine hairlike setae on dorsal surface; ocular lobe with lenses and pigment; pseudorostral lobe with small distal teeth; branchial concavity continuous; pereonites broader than long, first two pereonites with small teeth on dorsal surface; pleonites longer than wide, with fine teeth on lateral margins; uropods shorter than sixth pleonite.

Antenna 1 (Fig. 18 C) with first basal article shorter than the rest articles together; second article shorter than third article; main flagellum biarticulate; accessory flagellum uniarticulate and reduced. Antenna 2 (Fig. 18 D) peduncle with at least four articles; fourth article longer than all articles, flagellum with long articles and extending beyond abdomen. Labium (Fig. 18 E) with a plumose seta on dorsal surface and endite bilobulated. Mandible (Fig. 18 F) incisor process lost and lacina mobilis with three cusps. Maxillule (Fig. 18 G) with two endites, outer endite with ten cuspidate setae, inner endite with three setae. Maxilla (Fig. 18 H) with three endites, broader endite with 13 setae, medial narrow endite with six setae, and distal narrow endite with seven simple setae. Maxilliped 2 (Fig. 18 I) with ischium narrow at base; merus and carpus of the same length; carpus broader than propodus; dactylus pointed. Maxilliped 3 (Fig. 19 A) with basis expanded and a row of fine hairlike setae on the inner margin; ischium longer than merus; carpus shorter than propodus; dactylus about a third of the propodus, with an apical cuspidate seta.

Pereopod 1 (Fig. 19 B) with basis expanded, with four hyaline flattened setae on the outer margin; ischium and merus of the same length; carpus longer than propodus; propodus approximately two times the length of the dactylus; dactylus with six setae. Pereopod 2 (Fig. 19 C) with basis expanded, with serrate hyaline lamella and four flattenated setae on the outer margin; ischium fused to the basis; merus and carpus of similar proportions; propodus a half the length of the dactylus; dactylus with six cuspidate setae. Pereopod 3 (Fig. 19 D) with basis expanded; merus shorter than carpus; carpus and propodus of the same length; dactylus curved and pointed. Pereopod 4 (Fig. 19 E), basis with similar length as the rest of the articles together; merus longer than carpus; carpus shorter than propodus; propodus longer than dactylus; dactylus curved and pointed. Pereopod 5 (Fig. 19 F) basis shorter than the rest of the articles together, with fine hairlike setae on dorsal surface; merus shorter than carpus; carpus and propodus of similar length; dactylus curved.

Uropod (Fig. 19 G) short and robust; peduncle shorter than sixth pleonite, with two distal cuspidate setae on the inner margin; exopod biarticulate, terminal seta longer than both articles together; endopod longer than exopod, uniarticulate.

Ovigerous female, 1.8 mm (Figs 20 A–B). The overall appearance similar to the male. Carapace with small teeth on the middorsal line; frontal lobe a third of the length of the carapace; ocular lobe only with pigment. In lateral view, antero-lateral margin with fine teeth.

Antenna 1 (Fig. 20 C) similar to the male, but second and third basal articles with pappose and fine hairlike setae on dorsal surface. Maxilliped 1 (Fig. 20 D) basis with fine hairlike setae on dorsal surface; ischium fused to the basis; merus expanded, with fine hairlike setae on dorsal surface and two distal pappose setae; carpus broader than propodus, with seven flattenated setae on the inner margin; propodus longer than dactylus; dactylus with three apical setae, one robust. Maxilliped 2 (Fig. 20 E) with merus shorter than carpus; carpus longer than propodus; dactylus with cuspidate seta. Maxilliped 3 (Fig. 20 F) basis with six plumose setae and a small simple seta on the inner margin; ischium shorter than merus; merus longer than carpus; dactylus about a half the length of the propodus.

Pereopod 1 (Fig. 21 A) basis shorter than the rest of the articles, with two distal pappose setae and a row of fine hairlike setae on the inner margin; carpus and propodus of similar length; dactylus with a strong and pointed cuspidate seta. Pereopod 2 (Fig. 21 B) ischium short and bare; merus broader than carpus; propodus about a third of the length of the dactylus; dactylus with nine cuspidate setae. Pereopod 3 (Fig. 21 C) merus broader than carpus; carpus shorter than propodus. Pereopod 4 (Fig. 21 D) with merus longer than carpus. Pereopod 5 (Fig. 21 E) carpus shorter than propodus.

Uropod (Fig. 21 F) peduncle with two distal serrate setae on the inner margin; exopod with terminal seta shorter than both articles together.

Etymology. The species name refers to Cristian Kraker (CIIDIR, Oaxaca), for his invaluable help and support.

Remarks. The only species previously known for this genus is Elassocumella micruropus (Zimmer, 1943b) described from Florida, western Atlantic. The comparison for this species is based on the redescription of Bacescu & Muradian (1977) because they present a more detailed description and drawings of this species. We only compare females because the male of E. micruropus is unknown. Elassocumella krakeri resembles E. micruropus but is distinguishable from this species by the following: E. krakeri has a continuous branchial concavity, while E. micruropus has the branchial concavity disrupted by a gentle depression; E. krakeri has the carapace with many teeth on anterolateral margin, whereas E. micruropus has a bare anterolateral margin; E. krakeri has the pereon longer than the carapace, whereas E. micruropus has the pereon and carapace of the same length; E. krakeri has fine hairlike setae on all the inner margin of the pereopod 1, while E. micruropus has only a few fine hairlike setae on the inner margin of the propodus of the pereopod 1; E. krakeri has four fine hairlike setae on the dorsal surface of the basis of the pereopod 3, while E. micruropus has 16 groups of fine hairlike setae; E. krakeri has the peduncle of the uropod with two distal pappose setae, whereas E. micruropus has two cuspidate setae.