Monsamnis carpolongus Richard, Grave & Clark, 2012, sp. nov.
Creators: name: Richard, Jasmine
name: Grave, Sammy De
name: Clark, Paul F.
Publisher: name: Zenodo
Year: 2012
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Atyidae
Monsamnis
Monsamnis carpolongus

description: Monsamnis carpolongus sp. nov.
(Figs. 1–2)
Material examined. Holotype, 1Ƥ ovig., field number Wi08-0387, Sahamalaotra, Farihin-d’Rakotomainty, Ranomafana National Park, SE Madagascar, 21°14.216ʹ S 47°23.810ʹ E, elevation 1124 m, slow moving stream, sandy substrate, stream depth 6.37 cm, coll. Strauß et al., 0 1.02.2008, NHM reg. 2011.1976. Paratypes, 33, same data as holotype, OUMNH.ZC.2011-09-0021; 1Ƥ ovig., field number Wi07-0322, Sahateza, Ranomafana National Park, SE Madagascar, 21°15.476ʹ S 47°21.538ʹ E, elevation 1147 m, slow moving stream, very fine sandy substrate, stream depth 17.5cm, coll. Strauß et al., 0 2.03.2007, OUMNH.ZC.2011-09-0022; 33, 5Ƥ (+1Ƥ abnormal), field number Wi07-0278, Sahamalaotra Bridge, Ranomafana National Park, SE Madagascar, 21°14.113ʹ S 47°23.767ʹ E, elevation 1144 m, slow moving stream, substrate dead leaves, stream depth 12.7 cm, coll. Strauß et al., 22.2.2002, NHM reg. 2011.1977–1985; 33, 1 Ƥ ovig., 1Ƥ, field number Wi08-0377, Sahamalaotra Farihin-d’Rakotomainty, Ranomafana National Park, SE Madagascar, 21°14. 216ʹ S 47°23.810ʹ E, elevation 1124 m, relatively fast moving stream, sandy substrate, stream depth 6.37 cm, coll. Strauß et al., 0 1.02.2008, NHM reg. 2011.1986–1990.
Description. Size: TL: 15–25 mm; CL: 3–5 mm.
Rostrum (Fig. 1 a, b): 0.9–1.2 mm in length; triangular in dorsal view, not laterally compressed, equal to or shorter than length of eye, 0.2–0.35 as long as carapace, dorsally and ventrally unarmed.
Carapace (Figs. 1 a, b): lacking supraorbital, antennal and hepatic teeth, suborbital angle triangularly produced, frontal margin straight, pterygostomial angle not produced, angular.
Eyes (Fig. 1 a): well developed, anterior end reaching to 0.8 of basal segment of antennular peduncle, cornea well-developed, facetted, occupying distal 0.5 of eye, dorsal spot absent.
Antennular peduncle (Fig. 1 a, c): 0.45–0.6 carapace length, stylocerite 0.5–0.7 length of basal segment, anterolateral teeth of basal segment over reaching second segment 0.15–0.25; Scaphocerite (Fig. 1 d): well-developed, 2.5 as long as wide.
Mandibles (Fig. 1 e): asymmetrical, palp absent; incisor process furnished with several teeth, molar process truncated; left mandible with setose process between incisor and molar; right mandible lacking process, interval furnished setae.
Maxillula (Fig. 1 f): with lower lacinia subrectangular; upper lacinia short, inner margin setose; palp short, furnished with single seta.
Maxilla (Fig 1 g): with upper endites poorly divided; palp short; scaphognathite short, posterior extension poorly developed; bailer setae few, short.
First maxilliped (Fig. 1 h): as illustrated.
Second maxilliped (Fig. 1 i): typical for Atyidae, arthrobranch absent, podobranch well developed, laminar.
Third maxilliped (Fig. 2 a): reaching to end of antennular peduncle, ultimate segment 1.5 times length of penultimate one arthrobranch gills absent, pleurobranch gill present.
First pereiopod (Fig. 2 b): reaching with tip of chela to middle of scaphocerite, ischium short, 2.5 as long as wide; merus 4.0 as long as wide, approx. same length as carpus; carpus 3.1–3.5 as long as wide, excavated anteriorly, slightly shorter than chela; chela 3.0–3.5 as long as wide, distally with numerous serrulate setae; dactylus 1.0– 1.1 times length of palm of propodus.
Second pereiopod (Fig. 2 c): reaching with tip of chela to end of scaphocerite; ischium 4.0 as long as wide; merus 1.5 times length of ischium; carpus 1.5 times length of merus, 7–9 as long as wide, anteriorly excavated; chela 3.0–3.5 as long as wide, distally with numerous serrulate setae; dactylus approx. equal in length to palm of propodus.
Third pereiopod (Fig. 2 d, e): with propodal-carpal joint reaching to end of antennal scale; ischium 1.5 as long as wide, with a small spine medioventrally; merus 1.5–1.6 as long as carpus, with 1–3 larger spines along ventral margin; carpus 0.5–0.6 as long as merus, with subdistal spine; propodus 2.9–3.3 as long as dactylus, 9.0–11.0 as long as wide, with series of 9–10 spines along ventral margin; dactylus 0.5 length of propodus (terminal spines included), 3.2–3.6 as long as wide, flexor margin with 7–14 spines, additionally terminally with two, enlarged spines, distal one largest.
Fourth pereiopod: similar to third in form, but shorter, with distal spines on dactylus level with tip of rostrum; merus with 1–2 spines; carpus with 1 spine; propodus with 7–8 spines; armature of dactylus similar to third pereiopod.
Fifth pereiopod (Fig. 2 f, g): reaching past tip of rostrum by half length of propodus; ischium short; merus 1.5– 2.0 as long as ischium, with 1–2 spines along ventral margin; carpus 0.5–0.6 as long as merus, with single subdistal spine (small accessory spine in some individuals); propodus elongated, 2.2 as long as carpus, 9–10 as long as wide with 8–10 spines along ventral margin; dactylus 0.3–0.4 as long as propodus, 3.9–4.5 as long as wide, flexor margin with 65–85 spines, additionally terminally with two enlarged spines, distal one largest.
First male pleopod (Fig. 2 h, i): with endopod 0.45–0.6 times length of exopod; appendix interna present, subdistal margin furnished with cincunnuli, 9–12 spines present on the inner margin of endopod.
Second male pleopod (Fig. 23j, k): with endopod 0.8 length of exopod, appendix interna and masculina present; appendix masculina reaching to 0.7 length of endopod, 2.0–2.2 times length of appendix interna, internal surface covered with short spiniform setae.
Female pleopods: as usual for Atyidae, ovigerous females with 11– 14 eggs of 1.4–1.5 × 1.00– 1.1mm in size.
Sixth abdominal somite (Fig. 1 a): 0.65 as long as high, 0.4–0.5 length of carapace, as long as telson; lateral plate present, triangular.
Telson (Fig. 2 l, m): 0.5 times length of carapace, broadly rectangular, posterior margin broadly rounded; 2–4 pairs of dorsal spines, situated in posterior half; posterior margin broadly rounded with minute, median indent, one pair of disto-lateral spines present, as well as one pair of medio-lateral spines, medio-lateral ones longer; 7–12 partially plumose setae on distal margin increasing in length medially.
Uropod (Fig. 2 n): with exopod and endopod subequal in length, over-reaching telson by 1.3–1.4 of length; exopod with uropodal diaeresis complete, single, relatively large spine at disto-lateral corner.
Preanal carina (Fig. 2 o): unarmed.
Branchial formula (Table 1): Setobranchs all furnished with 5–6 plumodenticulate setae; exopod on fifth pereiopod reduced, usually vestigial, occasionally slightly more developed.
Etymology. The species name is formed by an arbitrary combination from the carpal segment (Latin, carpus) and the Latin longus with reference to the extended carpus of the second pereiopod being 7–9 times as long as wide.
Distribution. Known only from the type locality, Ranomafana National Park, SE Madagascar. Remarks. The three ovigerous Monsamnis carpolongus sp. nov. specimens carried a small number (11–14) of large eggs, 1.4–1.5×1.00– 1.1mm in size. In view of the few, large eggs spawned in this taxon and as well as the elevation of the locality of capture, abbreviated larval development probably occurs in this species with a substantial reduction in number of zoeal stages (Lai & Shy, 2009).
description: Published as part of Richard, Jasmine, Grave, Sammy De & Clark, Paul F., 2012, A new atyid genus and species from Madagascar (Crustacea: Decapoda: Caridea), pp. 31-38 in Zootaxa 3162 on pages 33-37, DOI: 10.5281/zenodo.215499