Elasmopus temori Barnard, 1979

García-Madrigal, María Del Socorro, 2010, Littoral Maeridae and Melitidae (Amphipoda: Gammaridea) from the Gulf of Tehuantepec, Mexico, Zootaxa 2623, pp. 1-51 : 3-7

Elasmopus temori Barnard, 1979

( Figs 1 , 2 )

Elasmopus temori Barnard, 1979: 75 , fig. 40 (part).

Type locality: Tower Island, Galapagos Islands.

Distribution: Galapagos Islands (Tower Island).

Habitat: depth 0–4; rock wash, sediments of coral rock, coral rock.

Material examined: 61 specimens: UMAR-PERA-223, 1 male, 3 females (one specimen mounted), 25 juv (Panteon beach, March 23, 2007, coral rock 3 m, coll. V. Mata); UMAR-PERA-224, 3 males (one male on slide), 9 females, 1 juv (Estacahuite beach, April 18, 2005, sediments of coral rock 1–1.5 m, coll. R. Bastida et al.); UMAR-PERA-225, 1 juv (Estacahuite beach, December 1, 2006, sediments of coral rock 4 m, coll. R. Bastida et al.); UMAR-PERA-226, 6 males, 11 females, 1 juv (La Tijera beach, April 30, 2005, sediments from coral rock 4 m, coll. R. Bastida et al.).

Description: based on male, 4.8 mm, UMAR-PERA-224.

Head: the length is equal in size to the first two segments of pereon; anterior head lobe subtruncate corners round, inferior antennal sinus short and margin straight. Eyes long, anterior margin round and posterior margin nearly straight, pigment dark brown; width represents more 1/3 the length of head. Antenna 1 elongated, 3/5 the length of the body, first article of peduncle the same size as the second article, and the length of third article 2/3 the length of second article. Accessory flagellum with two articles, first article 2/3 longer than the second article. Antenna 2 setose, approximately 1/2 the length of the antenna 1, length of fourth article 1/5 longer than of article 5; first article flagellar 1/5 the length of fifth article.

Pereon: medium body, length 2/5 longer than length of the antenna 1; dorsally smooth; color off-white in alcohol. Coxae 1–4 wide, coxae 1 and 4 with slightly emarginated on anterior and posterior margin respectively, coxae 2 and 3 with straight and parallel margins, coxa 2 narrower, coxae 1–4 with elongated setae, formula for coxae 1–4: 5–2–2–1; coxae 5–6 with some short setae and robust setae, formula for coxae 5–6: 2–2; coxa 7 with rounded margin and short setae. Gnathopod 1: inner margin of dactyl with soth simple setae; subquadrate propodus, transverse palm margin and minutely denticulated, with numerous simple setae of medium size, three robust setae longer than of those of palm margin, one of this at inner angle, and two robust setae on inner subdistal palm margin. Gnathopod 2 with the length of propodus more than 1/3 longer than the dactyl; irregular oblique palm, slightly setose with short robust setae arranged sparsely; palm with one barely visible subquadrangle hump near dactylar hinge, the second is a short conical tooth, the third broadly truncate medial tooth diminishing, palm defined by strong and subtriangle tooth to receive dactyl. Basis of pereopods 1–2 with scarce long simple setae on posterior margin; basis of pereopods 3–4 with posterior margin nearly straight, minutely serrate and basis of pereopod 5 semicircular, normally serrate; pereopod 1 subequal in size to pereopod 3, pereopod 2 smaller, basis of pereopods 3–5 gradually enlarged and with short simple setae.

Pleon: epimera continuous with respect to general line of the body; epimeron 3 lightly straight on posterior edge, armed with short setae, ventral edge bearing robust setae, formula for epimera 1–3 is 1: 1–1–1, 2: 2–2–1–1, 3: 1–1–2–1–2–1–1, with medium-sized setae on the first three positions of epimeron 3. Uropod 3 with peduncle 1/3 shorter than the outer ramous; inner ramous 1/4 shorter than the outer ramous; external margin of inner ramous bearing short robust setae in two positions, one robust seta proximal and two robust setae medial; external margin of outer ramous with two clusters of mediodistal short robust setae. Telson deeply cleft, with deeply excavated apices, armed with three robust setae, one long medial robust seta and two small robust setae, outer robust seta shorter than the inner robust seta, length of longest robust seta is 1/10 shorter than the length of the lobe, with two plumose setae in each lateral margin.

Female: based on female, 7.3 mm, UMAR-PERA-223. Gnathopod 1 similar to male, but only with one robust seta on inner angle of palm. Palm margin of gnathopod 2 with robust setae, length of dactyl 1/2 shorter than the propodus; one robust seta at angle of palm and one longer on inner submargin of palm; inner margin of dactyl minutely denticulated. Formula for epimera 1–3 is 1: 2, 2: 1–2–2, 3: 1–1–2–2–2, without setae. Uropod 3 with inner ramous 1/4 smaller than the outer ramous, inner margin of inner ramous with two sets of robust setae: one subdistal and one medial; only one robust seta near peduncle hinge. Telson resembles male, but with 3–4 apical robust setae and one plumose seta, length of longest robust seta is 1/5 shorter than the length than the lobe.

Taxonomic comments: Elasmopus temori from the Gulf of Tehuantepec presents some different character with the form from the Galapagos Islands, (see Table 1 ). Elasmopus temori from the Gulf of Tehuantepec has two robust setae located on the inner subdistal surface of the angle of the palm gnathopod 1, while that from the Galapagos Islands has one short robust seta. The middle tooth of gnathopod 2 from the Gulf of Tehuantepec is weak and widely truncate, while E. temori from the Galapagos Islands it is dissipated and widely conical. The formula of long setae for the coxae 1–4 in E. temori from the Gulf of Tehuantepec is 5–2–2–1, while that from the Galapagos Islands is 3–1–2–1. The formula of robust setae on ventral margin for the epimera 1–3 in E. temori from the Gulf of Tehuantepec is 1:1–1–1, 2:2–2–1–1, 3:1–1–2–1–2–1–1, while that from the Galapagos Islands is 1:2–1, 2:1–2–1, 3:1–2–2–2. The setae on ventral margin for the epimera 1– 2 in E. temori from the Galapagos Islands are medium-sized, while those from the Gulf of Tehuantepec are absent. Distal margin of peduncle of uropod 3 in E. temori from the Galapagos Islands has two medial short robust setae, while that from the Gulf of Tehuantepec has three. Number of short robust setae on inner margins of the inner ramous of uropod 3 in E. temori from the Galapagos Islands is 2, 2, 1, 1, while that of Gulf of Tehuantepec has only one and two short robust setae. Finally, outer margins of each lobe of telson in E. temori from the Galapagos Islands have two simple setae, while those of Gulf of Tehuantepec have only two plumose setae. Probably, the above characters may reflect the size or stage of maturity.

Gulf of Tehuantepec.

Remarks: according to Barnard (1979) by the similarity of E. temori with E. zoanthidea , he suggested that E. temori might be an aberration. Nevertheless, by the size of specimen illustrated, it is possible that Barnard (1979) described a pre-adult male from the Galapagos Islands. This species in the Gulf of Tehuantepec is observed as a valid species.

Figures

FIGURE 1. Elasmopus temori Barnard, 1979, male, 4.8 mm, UMAR-PERA- 224, Estacahuite beach, Oaxaca: A) habitus; B) accessory flagellum; C) coxa 1; D) coxa 2; E) coxa 3; F) coxa 4; G) coxa 5; H) coxa 6; I) coxa 7; J) gnathopod 2, external and internal side; K) gnathopod 1, external and internal side; L) epimera; M) uropod 3; N) left uropod 1; O) left uropod 2.

FIGURE 2. Elasmopus temori Barnard, 1979, male, 4.8 mm, UMAR-PERA- 224, Estacahuite beach, Oaxaca: A) right mandible; B) maxilliped; C) pereopod 1; D) pereopod 2; E) pereopod 3; F) pereopod 4; G) pereopod 5; H) maxilla 1; I) lower lip; J) upper lip; K) telson. Female, 7.3 mm, UMAR-PERA- 223, Panteon beach, Oaxaca: L) uropod 3; M) maxilla 2; N) telson; O) gnathopod 1, external side; P) gnathopod 1, internal side; Q) gnathopod 2, external side; R) gnathopod 2, internal side.

Tables

TABLE 1. Comparison between males of Elasmopus temori Barnard, 1979 from the Galapagos Islands and from the

Character/ species	Galapagos Islands	Gulf of Tehuantepec
Body length	4.17 mm	4.8 mm
Inner subdistal surface of angle of palm of gnathopod 1	One robust seta	Two robust setae
Middle tooth of gnathopod 2	Weak and widely conical	Dissipated and widely truncate
Long setae: formula for coxae 1–4	3–1–2–1	5–2–2–1
Spines on ventral margin: formula for epimera 1–3	1:2–1, 2:1–2–1, 3:1–2–2– 2–1	1:1–1–1, 2:2–2–1–1, 3:1–1–2–1– 2–1–1
Setae on ventral margin on epimera 1–2	With medium-sized setae	None
Number of spines on mediodistal margin of peduncle of uropod 3	2 short robust setae	3 short robust setae
Number of spines on inner margins of the inner ramous of uropod 3	2, 2, 1, 1	1, 2
Outer margins of each lobe of telson	Two simple setae	Two plumose setae