Edoneus sketi, Cai & Husana, 2009

Cai, Yixiong & Husana, Daniel Edison M., 2009, Cave Shrimps Of The Genus Edoneus Holthuis, 1978, From Luzon, The Philippines, With Descriptions Of Three New Species (Crustacea: Decapoda: Atyidae), Raffles Bulletin of Zoology 57 (1), pp. 51-63 : 57-60

Edoneus sketi , new species

( Figs. 4 , 5 )

Material examined. – Holotype: Male, cl 3.9 mm, NMCR, small pool in Bantakay Cave , Luzon, the Phippines, coll. D. E. Husana, 14 Dec.2002.

Paratypes: Seven males, cl 3.6–4.1 mm, 5 females, cl 4.2–4.5 mm, ZRC 2007.0485 , small pool in Bantakay Cave , Luzon, the Philippines, coll. D. E. Husana, 14 Dec.2002 ; 1 ovigerous female, cl 4.7 mm, ZRC 2007.0486 , small pool in Bantakay Cave , Luzon, the Phippines, coll. D. E. Husana, 14 Dec.2002 ; 2 male, cl 3.8–4.1 mm, ZRC 2007.0487 , small pool in Bantakay Cave , Luzon, the Phippines, coll. D. E. Husana, 14 Dec.2002 ;

Other materials: Eight males, cl 3.5–4.0 mm, 1 female, cl 3.6 mm, 2 ovigerous females, cl 4.0– 4.6 mm, eggs 1.0–1.1 × 0.6 mm, ZRC 2007.0488 , small pool in Bantakay Cave , Luzon, the Phippines, coll. D. E. Husana, 14 Dec.2002 ; 7 males, cl 3.7–4.0 mm, 9 females, cl 3.2–4.7 mm, 1 ovigerous female, cl 4.9 mm, eggs 1.0 × 0.6 mm, ZRC 2007.0489 , QM cave station 5, Luzon , the Phippines, coll. D. E. Husana, 14 Mar.2003 ; 4 males, cl 3.5–4.4 mm, 11 females, cl 3.5–4.6 mm, NMCR, QM cave station 7, Luzon , the Phippines, coll. D. E. Husana, 14 Mar.2003 .

Description. – Rostrum short ( Fig. 4A ), straight, reaching near to or slightly beyond end of basal segment of antennular peduncle, rostral formula 0–2(mode 0)+2–8(mode 0+2)/1–4, ventral teeth closely placed at anterior portion. Inferior orbital angle acute, indistinctly separated from antennal spine; pterygostomian margin sub-rectangular.

Sixth abdominal somite 0.55 times length of carapace, 1.7 times as long as fifth somite, as long as or slightly longer than telson. Telson ( Figs. 4B, C ) 2.5 times as long as wide, distal margin rounded, with a very tiny median projection, with 5 pairs of dorsal spinules, and one pair of dorsolateral spinules; distal end with 3–4 pairs of spines, lateral pair longer than intermediate pairs; sublateral pair shortest. Preanal carina ( Fig. 4D ) low, lacking spine.

Eyes strongly reduced, cornea only partially present, pigment reduced to a tiny dot or totally disappear; anterior end reaching to half length of basal segment of antennular peduncle. Antennular peduncle 0.5 times as long as carapace; basal segment of antennular peduncle as long as combined lengths of second and third segments, anterolateral angle 0.3 times length of second segment, second segment distinctly longer than third segment. Stylocerite reaching 0.8 times length of basal segment of antennular peduncle. Scaphocerite ( Fig. 4E ) 3.0 times as long as wide.

Incisor process of mandible ( Fig. 4F ) ending in a row of small teeth, molar process truncated. Lower lacinia of maxillula ( Fig. 4G ) broadly rounded, upper lacinia elongated, with numerous distinct teeth on inner margin, palp slender. Upper endites of maxilla ( Fig. 4H ) subdivided, palp elongated, scaphognathite tapering posteriorly with numerous long, curved setae at posterior end. Distal end of palp of first maxilliped ( Fig. 4I ) triangular, with a finger-like projection; flagellum of the exopod very short, endopod high, as long as flagellum of exopod in length. Second maxilliped ( Fig. 4J ) typical, except the slightly reduced arthrobranch. Third maxilliped ( Fig. 4K ) reaching to middle of third segment of antennular peduncle, with ultimate segment slightly longer than penultimate segment.

Epipods well developed on first four pereiopods. First pereiopod ( Fig. 5A ) reaching to anterior end of eye; merus 3.1 times as long as broad, as long as carpus; carpus excavated anteriorly, shorter than chela, 2.4 times as long as high; chela 2.3 times as long as broad; fingers 1.8 times as long as palm. Second pereiopod ( Fig. 5B ) long, reaching to middle of second segment of antennular peduncle; merus shorter than carpus, 6.7 times as long as broad; carpus 1.4 times as long as chela, 6.5 times as long as high; chela 2.6 times as long as broad; fingers 1.7 times as long as palm. Third pereiopod ( Figs. 5C, D ) reaching beyond scaphocerite by 1/5 of propodus, propodus 11.6 times as long as broad, 4.1 times as long as dactylus; dactylus 3.4 times as long as wide (spines included), terminating in two claws, 4–5 accessory spines on flexor margin. Fourth pereiopod reaching to end of antennular peduncle, similar in form as third one. Fifth pereiopod ( Figs. 5E, F ) reaching to end of antennular peduncle, propodus 16.8 times as long as broad, 3.7 times as long as dactylus; dactylus 4.0 times as long as wide

(spinules included), terminating in one claw, with 39–49 spinules on flexor margin.

Endopod of male first pleopod ( Fig. 5G ) sub-triangular, 2.3 times as long as wide, half length of exopod, no appendix interna. Appendix masculina of male second pleopod ( Fig. 5H ) sub-cylindrical, reaching to 2/3 length of endopod.

Uropodal diaeresis ( Fig. 5I ) with 17–20 movable spinules, outer most one distinctly longer than lateral angle.

Ovigerous female with eggs sized 1.0–1.1 × 0.6 mm.

Habitat. – See habitat under Edoneus erwini , new species.

Colouration. – Shrimps of the present species are found to have yellowish head and mostly unpigmented body.

Etymology. – The new species is named after Professor Boris Sket, University of Ljubljana, Slovenia, for his great contributions on the subterranean fauna of the Philippines, and for his encouragement to the current study.

Remarks. – With regard to the eyes, Edoneus sketi is morphologically close to E. atheatus . However, it can be distinguished by the longer rostrum, and more slender carpus of first pereiopod (2.4 times as long as high vs. 2.0 times in E. atheatus ).

Figures

Fig. 4. Edoneus sketi, new species: A, cephalothorax and cephalic appendages, lateral view; B, telson; C, distal portion of telson; D, preanal carina; E, scaphocerite; F, mandible; G, maxillula; H, maxilla; I, first maxilliped; J, second maxilliped; K, third maxilliped. Scale bars: A = 1 mm; B, K, E = 0.5 mm; C = 0.1 mm; D, F–J = 0.3 mm. (male, cl 4.1 mm, paratype, ZRC).

Fig. 5. Edoneus sketi, new species: A, first pereiopod; B, second pereiopod; C, third pereiopod; D, dactylus of third pereiopod; E, fifth pereiopod; F, dactylus of fifth pereiopod; G, male first pleopod; H, male second pleopod; I, uropodal diaeresis. Scale bars: A–C, E = 0.5 mm; D, F, I = 0.1 mm; G, H = 0.2 mm; (male, cl 4.1 mm, paratype, ZRC).