Elasmopus zoanthidea J. L. Barnard 1979

Elasmopus zoanthidea E. Pacific Elasmopus rapax complex

Galapsiellus leleuporum Indo-Pacifica Eriopisa

Heterophlias galapagoanus E. Pacific Heterophlias escabrosa

Elasmopus zoanthidea

ETYMOLOGY.—The epithet “zoanthidea” is from Greek, zoön (animal) and antheros (blooming).

DIAGNOSIS.—Eyes ordinary. Mandibular palp deeply falcate. Palm of male gnathopod 2 with ordinary spinose hump near dactylar hinge but hump weak, then broadly quadrate, weakly bifid or trifid, middle tooth separated from spinose hump by distance equal to width of hump 2, palm defined by obsolescent tooth on margin, palm and posterior margin of hand strongly setose throughout, medial face of hand with numerous bundles of setae in row paralleling palm and posterior margin. Article 2 of pereopods 3–5 lacking long posterior setae, article 2 of pereopods 4–5 normally serrate; locking spines of pereopods 3–5 ordinary, thin, straight, weakly striate longitudinally, inner locking spine on pereopods 1–2 enlarged, curved, blade-like, inner margin of dactyl on pereopods 1–2 with faintest shagreen, on pereopods 3–5 with occasional obsolescent serration, main subapical setule thick but apically flexible. Epimera bearing only short ventral spines, epimeron 3 weakly convex posteriorly, sparsely notched, posteroventral corner bearing weak sinus and weak, sharp tooth. Uropod 3 of male with shortened inner ramus bearing 2 pairs of medial spines. Telson with excavate apices armed with 3 spines, grading from short to greatly elongate from medial to lateral.

DESCRIPTION.—Generally like E. rapax (Figures 35–37) as follows: Eyes slightly smaller and with far fewer ommatidia, all stained brownish magenta, antennae 1–2 like E. rapax but article 1 of antenna 1 as in Figure 44: Alm, articles 2–3 with ventral setae elongate, accessory flagellum 3-articulate; mandibles like rapax but left mandible with first raker spine very thick and denticulate; upper lip, and lower lip like rapax; maxilla 1 with spines 2, 3, and 6 (from medial) each with 2 elongate and sharp side cusps, palp scarcely broader than outer plate; plates of maxilla 2 thinner than in E. rapax; dactyl of maxilliped shortened, main nail elongate, almost as long as dactyl; palm of gnathopod 1 with only 1 defining spine, medial comb of article 4 shortened, elements enlarged, article 5 with or without midanterior pair of setae; shapes of coxae 1–4 like those of E. rapax but elongate ventral setae fewer, formula of coxae 1–4 = 5–3–4–1, coxae 2–3 smaller relative to coxae 1 and 4 than in E. rapax; pereopods 1–2 generally as in E. rapax but spines and setae fewer; pereopods 3–5 and uropod 1 as in Figure 44, uropod 2 as in E. rapax but peduncle bearing only 1 dorsolateral spine set apically.

FEMALE.—Unknown.

HOLOTYPE.—USNM 169023, male “a,” 4.35 mm (illus.).

TYPE-LOCALITY.—GAL 113, Galapagos Islands, Tower Island (Genovesa), Darwin Bay, 29 January 1964, intertidal, rock wash.

VOUCHER MATERIAL.—Type-locality, male “v,” 4.41 mm (illus.) and 4 younger males.

RELATIONSHIP.—This species resembles E. holgurus in terms of telson and male gnathopod 2 but differs in the breadth and shape of the middle palmar tooth on male gnathoped 2, in the shallowness of posterior notches on article 2 of pereopod 5, and in the unextended epimeron 3. Other differences in setosity and shape may be a function of the small body size of E. zoanthidea and, therefore, juveniles of E. holgurus may resemble adults of E. zoanthidea in those characteristics.

Elasmopus zoanthidea resembles E. mayo and E. rapax especially in the palm of male gnathopod 2, but E. zoanthidea has many more setae on the medial face of the hand, lacks the protrusive medial limbs on the telsonic apices, and lacks long posterior setae on article 2 of pereopods 3–5.

MATERIAL.—GAL 102, 109, 113, 119; DAW 9, 23.

DISTRIBUTION.—Galapagos Islands, intertidal.

Galapsiellus J. L. Barnard