Elaphognathia alshumaimah sp. nov.

urn:lsid:zoobank.org:act: AF06EC94-3A95-4562-9E4D-D4ACBB022176

Figs 5–6

Elaphognathia sp. Al-Kandari et al. 2022: 118, fig. 3B.

Type material. Holotype. 1 ♂ (2.1 mm); Khor Al-Subiyah (Al-Shumaimah); 29° 39.403’N; 48°07.850’E; 24 November 2014, dead coral, 0.5–1.5 m (ZMH-K- 63976). Paratype. 1 Praniza (1.4 mm); same data as holotype, (ZMH-K- 63977).

Diagnosis. Frontal margin with deep excavation; a conical and acute mediofrontal process, bearing two fine long setae on each side. Mandible elongate, distally curved, with a single pronounced conical internal lobe. Lobi laterales absent on pereonite 6. Pylopod with three articles, third article minute.

Description of male. Body (Fig. 5 A) length 2.1 mm, about 3 times as long as wide.

Cephalosome (Fig. 5 A, B), about 0.7 times as long as wide. Supraocular lobe conical, rounded. Mediofrontal process present, conical, acute, each side with 2 fine long setae. Inferior frontolateral process small, serrated. Superior frontolateral process present, strong, with 4 fine long setae. Dorsal sulcus wide, deep, triangular. Eyes lateral, about 0.2 times as long as cephalosome length. Pereonites 1–6 (Fig. 5 A) without tubercles on dorsal surface, lateral margins smooth. Pereonites 1–2 subequal. Pereonite 1 dorsally reaching lateral margins, divided into 3 regions by posterior margin of cephalosome. Pereonite 3 smaller then the previous ones. Pereonite 4 longer and narrower than pereonite 3, with anterior constriction. Pereonite 5 with areae laterales. Pereonite 6 without lobi laterales; with weak lobuii. Pereonite 7 overlapping pleon, longer than pleonite 1, with rounded posterior margin. Pleonites 1–5 (Fig. 5 A), epimera visible dorsally, a row of 3 fine setae posteriorly on all pleonites. Pleotelson (Fig. 5 C) 0.95 times as long as anterior width; lateral margins smooth; mid-dorsal surface with 2 sub-median simple setae, posterolateral margins with 1 submarginal seta, apex with 2 long setae.

Antennula (Fig. 5 D) short, peduncle article 2 0.9 times as long as article 1; article 3 1.3 times as long as article 2; flagellum with 5 articles, about 1.25 times as long as peduncle article 3, articles 3–5 each bearing an aesthetasc. Antenna (Fig. 5 D) peduncle article 4 1.25 times as long as article 3, with 2 small sensory palmate setae ventrally; flagellum with 7 articles.

Mandible (Fig. 5 E) elongate, distally curved; about 1.3 times as long as cephalosome; with no obvious blade; with a single pronounced conical internal lobe, mandibular seta at midpoint.

Maxilliped (Fig. 5 F) article 1 lateral margin fringed with fine, small setae; endite extended beyond article 2; external margins of articles 2–5 bearing 2, 8, 5 and 7 stout plumose setae respectively; article 5 with 5 simple setae distally.

Pylopod (Fig. 5 G) with 3 articles; article 1 about 1.4 times as long as wide, lateral margin of article 1 with about 27 plumose setae; mesial and proximal margins with continuous fine setae, mesial margin with 2 submarginal long setae; distal end with 4 setae; article 2, 1.8 times as long as wide, fringed with dense fine setae, 6 long simple setae distally; article 3 minute.

Pereopod 2 (Fig. 6 A) basis 2.9 times as long as greatest width, superior margin with 2 long and 2sensory palmate setae, inferior margin 6 long setae; ischium 0.7 times as long as basis, merus as long as carpus; carpus inferior margin with 1 biserrate robust seta distally; propodus 3.4 times as long as wide, superior margin with 1 simple and 1 sensory palmate setae, inferior margin with 2 robust serrate setae. Pereopods 3 (Fig. 6 B) and 4 (Fig. 6 C) similar to pereopod 2. As illustrated Pereopod 5 (Fig. 6 D) is similar to pereopod 6 (Fig. 6 E).

Pleopod 1 (Fig 5 H) endopod and exopod with 8 plumose marginal setae; endopod longer than exopod, about 2.1 times as long as wide; exopod 2.3 times as long as wide; sympodite mesial margin with 2 coupling hooks, lateral margin with 1 stout simple seta. Pleopod 2 (Fig. 5 I) endopod and exopod shape as in pleopod 1, distally with 7 and 9 plumose marginal setae respectively.

Uropodal (Fig 5 C) rami extending beyond pleotelson apex, endopod and exopod nearly subequal in length, endopod wider than exopod. Endopod lateral margin fringed with small fine setae between 3 long setae; mesial margin weakly convex, with 7 long plumose setae. Exopod mesial and lateral margins fringed with small fine setae, between 10 long plumose setae.

Distribution. Only known from the type locality.

Remarks. Eight species of the genus Elaphognathia have been described from the Indian Ocean: E. aldabrae Kensley, Schotte & Poore, 2009 from Picard Island, Seychelles; E. amboinensis (Cals, 1978) from Indonesia; E. gladia Kensley, Schotte & Poore, 2009 and E. ramosa Kensley, Schotte & Poore, 2009 from Somalia; E. insolita (Stebbing, 1905) from Sri Lanka; E. korachaensis Svavarsson & Gisladottir, 2002: Andaman Sea; E. rangifer (Monod, 1926) from Thailand and Singapore and E. wolffi (Müller, 1989) from Kenya.

The new species is most similar to E. gladia Kensley, Schotte & Poore, 2009 in having a long, thin saber-like mandible. However, it differs from E. gladia in having a mandible with only one conical lobe at its base (vs two in E. gladia) and having an acute mediofrontal process (vs absent in E. gladia).

Elaphognathia bacescoi (Kussakin, 1969) from the Black Sea is also similar to the new species, but the former has a mandible with a bigger conical internal lobe, more setosed antenna and uropod rami.

Etymology. The name refers to the type locality in the intertidal area of Al-Shumaimah at Khor Al-Subiyah, Kuwait.