Pontonides ankeri Marin, 2007, n. sp.

• Main Author: Marin, Ivan
• Format: Text
• Language: unknown
• Published: Zenodo 2007
• Subjects: Biodiversity; Taxonomy; Animalia; Arthropoda; Malacostraca; Decapoda; Palaemonidae; Pontonides; Pontonides ankeri; Pacific; Queensland; Miers; Seta; Northwest Atlantic
• Online Access: https://dx.doi.org/10.5281/zenodo.6243321; https://zenodo.org/record/6243321

Pontonides ankeri n. sp. (Figs. 1 –3, 10 B, 11 F, G) Pontonides unciger.— Davis & Cohen, 1968: 749.— Heard, 1986: 481 (part.).— Fransen, 1994: 136.— Debelius, 2001: 194 (not Pontonides unciger Calman, 1939). Type material. Holotype. Vietnam, Nhatrang Bay: 1 ovig. female (pcl. 2.0 mm), Nok I., depth 15 m, on Cirripathes sp., coll. I. Marin, 29 May 2006, ZMMU Ma 5480. Allotype. Vietnam, Nhatrang Bay: 1 male (pcl. 1.4 mm), same data as for holotype, ZMMU Ma 5481. Paratypes. Vietnam, Nhatrang Bay: 1 ovig. female (pcl. 2.6 mm), 1 male (pcl. 2.1 mm), Nok I., depth 15 m, on Cirripathes sp., coll. I. Marin, 2 July 2006, ZMMU Ma 5482; 1 ovig. female (pcl. 4.0 mm), Tre I., Mui Nam, depth 8-10 m, on Cirripathes sp., coll. I. Marin, 11 July 2006, ZMMU Ma 5483; 1 ovig. female (pcl. 2.5 mm), 2 juveniles (pcl. 1.2, 1.0 mm), Tre I., Mui Nam, depth 10 m, on Cirripathes sp., coll. I. Marin, 11 July 2006, ZMMU Ma 5484. Diagnosis. Medium-sized pontoniine shrimps with subcylindrical body. Carapace smooth, gibbous. Rostrum short, not reaching distal margin of basal antennular segment in females, long reaching distal margin of basal antennular segment in males. Supraorbital margin well developed, rectangular; orbits well developed. Eyestalk without dorsal tubercle. Fourth and fifth pleura with produced posterodorsal angle. Second maxilliped with ischium bearing several plumose setae, without fusiform setae. Third maxilliped with numerous fusiform setae along proximal half of basal segment. First to fifth pereiopods without fusiform setae on ischia. Second pereiopods unequal; surface of major chela covered with tiny tubercles, setose; fingers stout and curved; minor chela sparsely setose; fingers about three times as long as wide, with curved tips. Third pereiopods setose; dactylus simple, curved, distally acute. Description. Female holotype, tl. 5.4 mm, pcl. 2.0 mm. Carapace smooth, gibbous, with well developed antennal tooth (Fig. 2 A, B); hepatic tooth absent; anterolateral angle broadly concave. Rostrum slender, short, not reaching distal margin of basal antennular segment, oval in cross-section (Fig. 2 A, B). Supraorbital carina well developed, broadly expanding over proximal part of eyestalk, forming pronounced supraocular eave, reaching to rostrum mid-length, with rectangular lateral margins. Abdominal somites smooth, tergites non-carinate or posteriorly produced; pleura of first to third abdominal somites posteroventrally rounded; pleura of fourth and fifth segments with produced posterodorsal angle (Fig. 1). Telson slender, 3–3.5 times as long as wide, not tapering distally, with two pairs of small submarginal dorsal spines situated at about 0.5 and 0.8 of telson length, respectively; posterior margin with three pairs of spines: smaller lateral spines, much stouter and longer intermediate spines, and slender plumose submedian spines, latter subequal to intermediate spine in length (Fig. 3 G). Eyes large, well developed, cornea and eyestalk rounded. Antennules (Fig. 2 D) with basal segment about twice as long as wide; lateral margin with strong acute distolateral tooth and distinct lobe between distolateral tooth and base of the next segment. Antenna (Fig. 2 E) with distolateral margin of basicerite rounded, without distolateral tooth; scaphocerite broad, not exceeding antennular peduncle and rostrum, about 1.5 times as long as maximum wide, with well developed distolateral tooth. Mouthparts without specific features, typical for genus. Mandible (Fig. 2 F) without palp; incisor process slender, tapering distally, with three terminal teeth; molar process well developed. Maxillula (Fig. 2 G) normal; palp well developed, bilobed; upper lacinia larger than lower, slightly tapering distally, with strong distal spines; lower lacinia slender, distally rounded, with distal setae. Maxilla (Fig. 2 H) with well developed simple rounded palp. First maxilliped (Fig. 2 I) with completely fused endites; palp with distal setae; exopod greatly reduced (Fig. 2 J). Second maxilliped (Fig. 2 K) with ischium furnished with several plumose setae in central portion of mesial margin; epipod oval, without podobranch. Third maxilliped (Fig. 2 L) with broad segments, lateral margin of basal segment with numerous fusiform setae in proximal half (Fig. 2 M); exopod well developed; arthrobranch present. First pereiopods (Fig. 3 A) slender, unarmed; palm (Fig. 3 B) about twice as long as wide, subcylindrical; fingers slender, about three times as long as wide, with straight cutting edges and row of stiff setae at tips. Second pereiopods unequal (Fig. 3 C, D); major chela (Fig. 3 D) with papillose and setose palm; fingers stout, about twice as long as wide, curved, with well developed dentate cutting edges (Fig. 3 E); minor chela (Fig. 3 C) with smooth but setose palm; fingers slender, about four times as long as wide, with unarmed cutting edges. Third to fifth pereiopods (Fig. 3 F) stout, smooth; dactylus simple, curved. Pleopods not especially modified. Uropods slender, exceeding telson; lateral margin of endopod with movable spine, without distal tooth (Fig. 3 H). Male allotype (Fig. 1), tl. 4.2 mm, pcl. 1.4 mm. Generally similar to holotype female, although smaller and slenderer. Endopod of second pleopod with well developed appendix masculina bearing three simple setae along lateral margin and one long simple terminal seta (Fig. 10 B). Colouration (Fig. 11 F, G). Carapace generally pale-translucent, with three broad pale yellow or whitish transverse bands, first crossing carapace between eyes, second at about carapace mid-length, and third just in front of posterior margin; abdomen generally pale-translucent, with two broad pale yellow to whitish transverse bands over second and third segments; distal portion of fourth, entire fifth segment, telson, as well as eyes and appendages uniformly pale yellow (colour fading at night, with bands becoming less conspicuous due to chromatophore contraction, I. Marin, pers. obs.). Size. Maximum length: ovigerous female, cl. 4.8 mm, pcl. 4.0 mm, tl. 14.5 mm; male, cl. 2.5 mm, pcl. 2.1 mm, tl. 7.0 mm. Type locality. Nhatrang Bay, Vietnam. Etymology. The species is named in honour of my friend and colleague, Dr. Arthur Anker (currently at the Smithsonian Tropical Research Institute, Panama City, Panama). Size. Maximum length: ovigerous female, cl. 4.4 mm, pcl. 4.0 mm, tl. 9 mm; male, cl. 2.8 mm, pcl. 2.1 mm, tl. 8 mm. Eggs numerous, diameter 0.3 x 0.4 mm Ecology. In Nhatrang Bay, this species was found on sea whips, Cirripathes sp. (Antipatharia, Antipathidae), mainly in heterosexual pairs or one pair with several juveniles per host, in the depth range between 10 and 35 m. Mature individuals seem to prefer a position near the base of the sea whip, while juveniles usually occur closer to the tip. Systematic position. Pontonides ankeri n. sp. is morphologically most similar to P. l o l o a t a Bruce, 2005, differing from it by the longer rostrum, and the lateral carinae continuing only to the middle of the rostrum (vs. to the tip of the rostrum in P. l o l o a t a , see Bruce 2005). The two species also differ by their colour patterns. In P. ankeri n. sp. , the carapace is crossed by two conspicuous broad transverse pale or pale-yellow bands (not counting a narrow anterior band between the eyestalks), and the carapace flanks are uniform pale-yellow, without brown dots (Fig. 11 F, G). In contrast, in P. l o l o a t a , the carapace is crossed by only one conspicuous broad transverse pale or pale-yellow band (not counting a narrow anterior band between the eyestalks), and the carapace flanks are speckled by light brown dots (Fig. 11 H). Pontonides ankeri n. sp. can be separated from the remaining species of Pontonides by the distinctly gibbous carapace and some other features (see key below). Distribution. Based on previous records (see Bruce, 2005), numerous photographs in popular underwater guides and in the internet, and the present record, P. ankeri n. sp. appears to be widely distributed in the Indo- West Pacific, e.g., in the Seychelles, Thailand, Vietnam, Philippines, Indonesia, Papua New Guinea, Taiwan, Japan, Australia, French Polynesia and Hawaii (but see remarks below). Remarks. Because of previous misidentifications of P. a n k e r i n. sp. it is presently impossible to determine its host specificity and distribution range. This species (or a very similar species) was reported, mostly under the names “ P. unciger ” or “ Pontonides sp.”, from various Cirripathes species (e.g., C. anguina (Dana, 1846)) throughout the Indo-West Pacific (e.g., Grigg 1964; Davis & Cohen 1968; Castro 1971; Bruce 1977; Monod 1979; Fransen 1994; Jeng, 1998; Hoover 1998; Debelius 2001; Kawamoto & Okuno, 2003; for more references see also Bruce, 2005). Some of these records may actually refer to P. ankeri n. sp. (e.g., Gosliner et al. 1996; Debelius 2001; Kawamoto & Okuno 2003), although examination of specimens is always necessary to provide positive identification. Bruce (2005) suggested that the shrimp illustrated as “ Pontonides sp. 2 ” by Minemizu et al. (2000) may be P. l o l o a t a based on the presence of only one broad conspicuous yellow band running across the carapace and brownish dots on the carapace flanks. However, this individual also has an indication of a second pale yellow band near the posterior margin of the carapace; therefore, it’s identification as P. loloata should be regarded as unconfirmed, also because both P. loloata and P. ankeri n. sp. appear to be present in southern Japan. Finally, “ P. unciger ” in Lieske & Miers, (2004) and “ Pontonides sp. 2 ” in Hoover (1998) and Minemizu (2000, small photograph on p. 69) probably represent a further undescribed species characterized by the bright greenish-yellow dots arranged in diffuse transverse bands on the carapace and abdomen. : Published as part of Marin, Ivan, 2007, The coral-associated shrimp genus Pontonides (Caridea, Palaemonidae, Pontoniinae) in Nhatrang Bay, Vietnam, with description of two new species, pp. 1-21 in Zootaxa 1635 on pages 3-8, DOI: 10.5281/zenodo.179514 : {"references": ["Davis, W. P. & Cohen, D. M. (1968) A gobiid fish and a palaemonid shrimp living on an anti- patharian sea whip in the tropical Pacific. Bulletin of Marine Science, 18, 749 - 761", "Heard, R. W. (1986) Pontoniine shrimps (Decapoda: Caridea: Palaemonidae) of the northwest Atlantic, I: The genus Neopontonide s Holthuis, 1951, with the description of N. chacei, new species, and the erection of Pseudopontonides, new genus, to receive N. principis Criales, 1980. Journal of Crustacean Biology, 6, 471 - 484.", "Fransen, C. H. J. M. (1994) Marine palaemonid shrimps of the Netherlands Seychelles Expedition 1992 - 1993. Zoologische Verhandelingen, 297, 85 - 152.", "Debelius, H. (2001) Crustacea guide of the world. IKAN UW-Archiv, Frankfurt, Germany. 322 pp.", "Calman, W. T. (1939) Crustacea: Caridea. In: The John Murray Expedition 1933 - 34 Scientific Report, 6, 183 - 224.", "Bruce, A. J. (2005) Pontoniine shrimps from Papua New Guinea, with description of two new genera, Cainonia and Colemonia (Crustacea: Decapoda: Palaemonidae). Memoirs of the Queensland Museum, 51, 333 - 383.", "Grigg, R. W. 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