Tanystylum geminum Stock 1954
Creators: name: Müller, Hans-Georg
name: Krapp, Franz
Publisher: name: Zenodo
Year: 2009
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Pycnogonida
Pantopoda
Ammotheidae
Tanystylum
Tanystylum geminum

description: Tanystylum geminum Stock, 1954   
Fig. 18–19  
 Tanystylum geminum Stock, 1954: 120.— Child 1979: 28. Stock: 13. Stock, 1982: 187. Stock 1986: 400. Müller 1990: 279. Müller 1992:45   
 Material. 19.— 2 fem. (gravid) (SMF 1404), Thalassia, 5 l of substratum, 0.5–4 m, 27.VI.1985. 1 fem. (gravid) (SMF 1405), Thalassia, 5 l of substratum, 5.VII.1985. 1 fem. (gravid) (SMF 1406), Thalassia, 5 l of substratum, 9.IX.1985. 1 male (SMF 1407), Thalassia, 5 l of substratum, 8.XI.1985. 2 males, 1 fem., 2 juv. (SMF 1408), Thalassia, 5 l of substratum, 7.XII.1985. 1 juv. (SMF 1410), Thalassia, 5 l of substratum, 12.II.1986.   
 24.— 2 males, 1 fem., 2 juv. (ZMA 3387), Thalassia, 0.5–1 m, 8.XI.1985. 1 juv. (SMF 1411), Thalassia with corallinacean algae, 1 m, 21.I.1986.   
 32.— 1 male (SMF 1412), on brown algae (mainly Sargassum) on rock, mesolittoral, 3.VIII.1985.   
 34.— 1 fem. (SMF 1413), on brown algae, Thalassia and hydroids, 0.5–2 m, 30.VII.1985.   
 40.— 1 male (ov.), 5 fem. (gravid) (SMF 1414), Thalassia, 1–3.5 m, 8.VIII.1985.   
 43.— 1 male (SMF 1415), Thalassia, 1–1.5 m, 25.II.1986.   
 Description of male: Dorsal trunk outline circular, crurigers touching along their entire length, smooth and without any setae; all segments fused. Cephalon with two short antero-lateral setae above palp origin. Ocular process broader than high, eyes relatively large and distinctly pigmented. Abdomen relatively short, directed obliquely to the rear, with 4 short setae in its distal part; abdomen surpassing the 4 th crurigers by about 1/4–1/2 of its length. Proboscis relatively long, strongly narrowing in its distal third.   
 Cheliphores about 1/3 length of proboscis, fused in their median line, distally rounded and bearing 3–4 short setae. Palpus 4-articled, 2 nd article elongated; 4 th article two times as long as 5 th, bearing 6 ventral and 3 terminal spines. Oviger 10-articled; articles 4 and 5 elongated, of nearly equal length and bearing some short spines; articles 6–10 shortened, bearing some short spines.   
Legs robust, all articles bearing conspicuously few short spines and setae; coxae 1 of all legs distallydorso-laterally with a few irregularly shaped (partly branched) tubercles with short spines; coxa 2 with some short lateral spines, some mounted on tiny tubercles; coxae 1–3 subequal in length; dorso-distal cement gland on femur forming short and distally narrowing tube; tibia1 and 2 subequal in length, with 2 flat roundish dorsal tubercles; tarsus as long as broad, 4 ventral spines; propodus moderately curved, with indistinct heel; proximal third of sole with 3 strong short spines; sole distally with 3 small spines and about 4 short setae; main claw feebly curved, half as long as propodus; auxiliaries nearly straight, 2/3 length of main claw.  
 In contrast to the brownish colouration of most other species in this genus, T. geminum in our samples is whitish-yellow.   
 Measurements: Trunk length 0.47; width (across 2 nd crurigers) 0.50; length of abdomen 0.13; proboscis length 0.34. Leg 3: coxa 1, 0.12; coxa 2, 0.13; coxa 3, 0.13; femur 0.34; tibia 1, 0.28; tibia 2, 0.30; tarsus 0.06; propodus 0.28; main claw 0.14; auxiliary 0.09.   
 Female: In habitus like male, coxae 1 and 2 of all legs with some short setae distally. Oviger distinctly shorter than in male, in total more sparsely spinose and articles 4–5 more shortened.   
 Remarks: T. geminum is easily recognizable by its well-developed cheliphores, lack of tubercles and setae on the crurigers, and light colouration in the samples. This species is strikingly similar to Tanystylum bredini Child, 1970, which is widely distributed in the Indo-Pacific. Distinctly differentiating characters are the shape of the proboscis, which is more robust in T. bredini and distally not so strongly narrowing, and shorter than the palps. Stock’s (1982: 187) material from Somalia, which he considered with some reservation as T. geminum, is comparable to the T. bredini which Müller (1990c: 68, Figs. 7–10) reported and figured from Kenya.   
 T. geminum predominantly colonized Thalassia stands in the research area, although to a lesser degree it was found also in association with algae. The depth range was from the mesolittoral to about 4 m. A single ovigerous female was found in VII only. Mature specimens were found during the course of the entire year except in the months III and X–XI.   
 Distribution: Atlantic coast of Mexico and Panamá (Child 1979: 28), Florida and Puerto Rico (Stock 1975a: 983), Barbados (Müller, 1992), Martinique (Bourdillon 1955: 587; Müller 1990d: 279), Bonaire, Isla Margarita, St. Martin and Jamaica (Stock 1979: 13).
description: Published as part of Müller, Hans-Georg & Krapp, Franz, 2009, The pycnogonid fauna (Pycnogonida, Arthropoda) of the Tayrona National Park and adjoining areas on the Caribbean coast of Colombia 2319, pp. 1-138 in Zootaxa 2319 (1) on pages 42-43, DOI: 10.11646/zootaxa.2319.1.1, http://zenodo.org/record/5317868