Athanopsis tarahomii, Marin, Ivan, Sheibani, Raheleh & Sari, Alireza, 2014

Marin, Ivan, Sheibani, Raheleh & Sari, Alireza, 2014, A re-description of rare alpheid shrimp Amphibetaeus jousseaumei (Coutière, 1896) and description of a new species of the genus Athanopsis Coutière, 1897 (Crustacea: Decapoda: Alpheidae) from Iranian coast of the Persian Gulf, Zootaxa 3846 (3), pp. 398-410 : 404-409

Athanopsis tarahomii sp. nov.

( Figs. 4–7 )

Material examined. — Holotype, male (cl. 8.0 mm, tl. 22.0 mm) (SMF-43233); paratype, female (cl. 9.0 mm, tl. 23.0 mm) ( ZUTC Nat. 1118)—Northwest Indian Ocean, the Persian Gulf, Iran, Qeshm Island, 26º51′N, 56º08′E, subtidal, under stone, 11Jan2008.

Description.— Medium-sized robust shrimp. Carapace ( Fig. 4 a–c) glabrous, smooth, unarmed; orbital hoods partly covered eyes, extra-cornea tooth blunt, well marked, adrostral furrow deep, rounded. Rostrum well developed, in lateral view, deep, compressed, curved downward, about 1.5 times as long as wide at base, dorsal margin with small rounded tooth at distal third; median side with laminal plate reaching to distal third of rostrum; tip rounded, reaching to the middle of the second antennular segment ( Fig. 4 a, b, d, e). Rostrum in dorsal view, broad triangular with median ridge, as long as proximal width, tip bluntly pointed ( Fig. 4 c). Pterygostomial angle slightly produced, bluntly rounded ( Fig. 4 a, d, e).

Antennular peduncle ( Fig. 4 h) robust; first segment stout, about 1.5 times longer than distal width, stylocerite large, with convex lateral margin, tip bluntly pointed, reaching to the midlength of second segment, mesial margin with blunt small tooth; second segment subequal to third segment, about as long as wide, upper flagellum short, biramous, with 3–4 proximal robust and partly fused segments, shorter ramus with 9 segments and each with group of 3 aesthetascs, longer ramus with more than 30 segments, lower flagellum longer than upper.

Antenna ( Fig. 4 a) robust, with robust basicerite bearing large sharp dorsolateral tooth and acute ventral tooth; carpocerite overreaching scaphocerite, scaphocerite well developed, about 2.5 times longer than maximum width, with small distolateral tooth reaching beyond the blade. Flagellum longer than postorbital carapace length. Antennal gland opening on small process.

Abdomen smooth, ventrolateral posterior border of fourth and fifth somites pubescent, sixth somite with movable bluntly rounded triangular plate at posterolateral edge ( Fig. 4 g). Telson ( Fig. 4 f, g) with slightly convex lateral margins, about 1.4 times as long as maximaum width, about 1.3 length of sixth abdominal somite, with posteriorly rounded margin about half of proximal margin, dorsal surface with 2 pairs of small submarginal spines, anterior part situated in midlength of telson; distal margin with numerous long setae and submarginal row of short setae, lateral corner with one pair of spines, mesial spine about twice longer than lateral spines.

Uropods with sympodite greatly produced distally, sharp pointed, tip reaching little less than half of exopod ( Fig. 4 f, g); exopod shorter than endopod and telson, lateralmargin almost straight, dieresis with small acute distolateral tooth and long sublateral spine ( Fig. 4 i); endopod normal.

Mouthparts typical of genus. Mandible ( Fig. 5 a) robust, with strong molar process, incisor process with 6–7 triangular teeth along distal margin, palp 2-segmented, tip reaching to the midlength on molar process. Maxillula ( Fig. 5 b) with bilobed palp, distal lobe bearing one row of small setae distally, proximal lobe with single long seta; distal lacinia with setae and short blunt spines distally, proximal lacinia slender with several long spines and numerous setae distally. Maxilla ( Fig. 5 c) with tapering palp, proximal endite short and thumb-like, distal endite bilobed, distal lobe with setae mesially, proximal lobe small; scaphognathite broad, with marginal setae. First maxilliped ( Fig. 5 d) with epipod large and broad; palp long, rather broad, bluntly pointed with plumose apical seta; mesial margin with setae; exopod long and slender, caridean lobe feebly developed, with plumose setae laterally; distal endite broad, bilobed, proximal small, rounded. Second maxilliped ( Fig. 5 e) normal, with ear-shaped epipod and well developed long slender exopod. Endopod robust; ischiobasis, merus longer than carpus, carpus as long as wide; propodus with rounded distal lobe fringed with long setae; dactylar narrow, about 3 times wider than long, with numerous small teeth and simple setae along mesial margin. Third maxilliped ( Fig. 5 f) robust, exceeding antennular peduncle by tip of ultimate segment; epipod with terminal hook; exopod rather broad, subequal to the length of antepenultimate segment; antepenultimate segment about 3 times longer than maximum width, significantly broadening distally; penultimate quadrate in shape, as long as wide; ultimate segment slender, about 3 times longer than penultimate, and 4 times longer than wide, tapering distally, mesial margin with 15–20 rows of setae distal corner with tufts of long simple setae ( Fig. 3 1 ).

First pereiopods unequal ( Fig. 6 a–d) in both size and shape, in male and female, heavier and wider in males, carried flexed beneath the body. Total length of major chela equal to postorbital length of carapace. Major cheliped ( Fig. 6 a, b) with basis stout, unarmed; ischium as long as wide, bearing 3 teeth on dorsal margin, ventral margin with well marked blunt triangular tubercle ( Fig. 6 b) merus unarmed, expanded distally, about 2.5 longer than maximum width, ventral margin excavated, ventrolateral margin strongly convex distally; carpus cup-shaped, about as long as wide, with sharply produced distoventral margin; palm unarmed, about 3.5 times longer than fingers, about 3 times as long as maximum width, mesial face strongly convex, ventral face excavated; fingers compressed with flattened tips, tips bearing 7-8 small triangular teeth, fixed finger about twice longer than wide, cutting edge unarmed; movable finger about 2.5 times as long as wide, curved downward, cutting edge with 2 large proximal teeth and 8 small triangular teeth along distal margin. Minor cheliped ( Fig. 6 c-d) rather slender; coxa about as long as wide, unarmed; ischium about 1.5 times as long as wide, unarmed, with small tubercle at ventral margin; merus about 3.5 times as long as wide, with straight margins, unarmed; carpus cup-shaped, slightly longer than wide, unarmed; palm ( Fig. 6 d) cylindrical, about 1.5 times longer than fingers, about 2.5 times as long as wide, surfaces smooth; fingers curved downward, about 3 times longer than wide, tips pointed, cutting edges bearing numerous small teeth.

Second pereiopod ( Fig. 6 e) slender; coxa with setobranch and stick-like epipod; basis about slightly longer than wide, unarmed; ischium about twice longer than wide and 2 times longer than basis, unarmed; carpus long, subdivided into 5 segments, with ratio about 8:1:1:1:2, with distal article subequal to length of palm; chela small, palm subequal to the length of fingers, about 1.2 times longer than wide, fingers simple, about 2.5 times as long as wide, tips sharply pointed.

Ambulatory pereiopods robust, similar in size and shape. Third pereiopod ( Fig. 6 f) with ischium armed with 2 spines on ventral margin, merus about 3 times as long as wide, dorsal margin slightly convex, unarmed, distoventral corner obtusely angulated; carpus about 2.3 times as long as wide, slightly expanded distally, ventral margin with 4 single spines and one pair of distal spines; dactylus stout, simple, slightly curved, about 2.5 times as long as propodus, about 2.5 times longer than proximal width, tip sharply pointed. Fourth pereiopod ( Fig. 6 g) with ischium armed with 2 spines on ventral margin, merus about 2.5 times as long as wide, with slight convex dorsal margin, dorsoventral corner obtusely angulated, unarmed; carpus about 2 times as long as wide, slightly expanded distally, distoventral margin with single spine, propodus about 3 times as long as wide, ventral margin with 3 single spines and one pair of distal spines; dactylus stout slightly curved, about 2 times as long as propodus, about 2.5 times longer than proximal width, tip sharply pointed. Fifth pereiopod ( Fig. 6 h) with ischium armed with 2 spines on ventral margin, merus about 2.5 times as long as wide, with straight dorsal margin, unarmed, distoventral corner obtusely angulated; carpus about 2 times as long as wide, slightly expanded distally, ventral margin with one pair of distal spines; propodus rather slender, about 4.5 times as long as wide, ventral margin with 2 spines and one pair of distal spines, distal margin with row of simple setae, dactylus stout, simple, slightly curved, about 4 times as long as propodus, about 2.5 times longer than proximal width, tip sharply pointed.

Endopod of male first pleopod about 4 times longer than width, tapering distally with 2 terminal plumose setae, medial border with 6 plumose setae and lateral border with 3 simple setae. Second pleopod with appendix masculina slightly shorter than appendix interna, about 5 times longer than wide, with 6-7 distal spines.

Differential diagnosis.— Recently the genus Athanopsis includes 6 described species such as a type species of the genus, A. platyrhynchus Coutière, 1897 from Djibouti; A. dentipes Miya, 1980 from sandy mud of Amakusa and Nagasaki, Kyushu, Japan; A. brevirostris Banner & Banner, 1981 from southern Red Sea, among corals; A. australis Banner & Banner, 1982 from sandy sediment of Port Phillip Bay, A. rubricinctuta Berggren, 1991 from Mozambique and A. saurus Anker, 2011 from Australia. The new species is the first record of the genus from the Persian Gulf. The new species can be clearly separated from other species of the genus by deep, curved downward rostrum and the presence of well marked blunt extra-cornea teeth. The new species can be clearly separated from A. platyrhynchus by deeper rostrum and expanded palm nd merus of the major cheliped; from A. dentipes by deeper, curved downward rostrum and well developed endites of maxilla and first maxilliped; from A. brevirostris by deep well developed rostrum, blunt extra-corneal teeth, shorter stylocerite of antenulla and; from A. australis by deeper rostrum, absence of meral ventral spine of third pereiopod, the presence of two spines on ischium of ambulatory pereiopods and broader telson; from A. rubricinctuta by deeper rostrum, the presence of well marked extra-corneal teeth, smooth lateral margin of propodus of major first pereiopod, shorter finger of minor first pereiopod and absence of meral ventral spine of ambulatory pereiopod. The most morphologically similar species is A. dentipes Miya, 1980 known from Japan.

Coloration. —General body and appendages are yellowish translucent; antennula, distal part of scaphocerite, dorsal margin of carapace and abdominal somites, telson and uropods covered with tiny red chromatophores ( Fig. 7 ).

Etymology.— This species named after the late PhD student M. Tarahomi who tragically passed away in Iran during field collection in October 2009.

Habitat.— The specimens were found on sandy soft bottom in cobble/rocky area under large boulder in association with echiurans similar to other species of the genus.

Distribution. —Presently the species is known from type locality, Qeshm Island, Iran, the Persian Gulf, only.

Figures

FIGURE 3. Amphibetaeus jousseaumei Coutière, 1896, a-g female, h male (SMF- 43232): a — carapace and appendages; b – c — first major pereiopod, different views; e, f— same, fingers; g — minor first pereiopod; h— same, chela.

FIGURE 4. Athanopsis tarahomii sp. n., a – d, f – i paratype female (ZUTC Nat. 1118), e holotype male (SMF- 43233) a, b— front of carapace, lateral view; c— same, dorsal view; d, e— rostrum; f, g— sixth abdominal segment, telson and uropods; h — antennula; i— distolateral margin of uropodal exopod.

FIGURE 5. Athanopsis tarahomii sp. n., paratype female (ZUTC Nat. 1118): a— mandible; b — maxillula; c— maxilla; d — first maxilliped; e — second maxilliped; f— third maxilliped.

FIGURE 6. Athanopsis tarahomii sp. n., paratype female (ZUTC Nat. 1118): a, b— major first pereiopod; c — minor first pereiopod; d — same, chela; e— second pereiopod; f — third pereiopod; g—fourth pereiopod; h — fifth pereiopod.

FIGURE 7. Alive coloration of paratype female (ZUTC Nat. 1118) of Athanopsis tarahomii sp. n.