Ascorhynchus latipes (Cole, 1906)

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, Zootaxa 2319 (1), pp. 1-138 : 59-61

Ascorhynchus latipes (Cole, 1906)

Fig. 29

Barana latipes Cole, 1906: 217 .

Ascorhynchus latipes ,— Child 1979: 15, (literature). Stock 1979: 969. Child 1982: 359. Stock 1986: 400.

Material: 12.— 1 fem. ( INVEMAR), Coral rubble, growth of Neofibularia , 10 m, 24.IX.1985 . 1 fem., 1 juv. ( ZSM) coral rubble, 17–19 m, 9.I.1986 .

22.— 3 fem. (1gravid), 5 juv. ( SMF 1113 ), on Halimeda upon reef surface, lower mesolittoral, 14.IV.1986 .

24.— 1 juv. ( SMF 1114 ), Thalassia with corallinaceaeous algae, 1 m, 21.I.1986 . 1 juv. ( SMF 1115 ), coral rubble, 7–8 m, 27.IX.1985 .

27.— 8 males (4 ov.), 4 fem. (1 gravid), 3 juv. ( SMF 1116 ), coral rubble among Thalassia , 1 m, 1.XI.1985 .

28.— 1 male (ov.), 1 fem. (gravid) ( SMF 1117 ), under stones, 0.5 m, 4.IV.1986 .

34.— 2 males ( SMF 1118 ), under stones, 0.5 m, 10.IV.1986 .

36.— 1 male (ov.) ( ZFMK), coral rubble, 11–16 m, 23.IX.1985 . 1 fem. (gravid), 2 juv. ( ZMA 3367 ), under stones, 0–0.5 m, 14.IV.1986 . 1 fem. ( MNHN), coral rubble, 13 m, 28.II.1986 .

Description of male: Trunk robust, dorsal outline a long oval, completely segmented; segments 1–3 adorned with cone-shaped dorso-median tubercle, which bear some short spines apically. Crurigers separated from each other by 1/3–1/4 of their diameter, dorso-distally with acute tubercle, and dorso-distally and laterodistally with 2–6 short spines. Cephalon barely longer than broad, with short pointed protuberance over origin of cheliphores; Cephalon slightly broadened at origin of palps, strongly so at origin of ovigers. Ocular process situated at anterior region of oviger origin, about as long as broad, distally with short tip; eyes distinctly pigmented. Proboscis a longish oval, broadest in its middle part, twice as long as broad, about 2/3 of trunk length. Abdomen protracted, reaching well over hind margin of first coxae of leg 4, directed horizontally, distally rounded; sparsely clad with short setae in dorsal and lateral positions.

Cheliphore scape relatively short, about twice as long as broad, with some dorsal and retro-lateral spines; chela a stump. Palp 10-articled, 3 rd and 5 th article prolonged, 5 th slightly shorter than 3 rd; 5 distal articles with numerous, mainly ventral setae. Oviger 10-articled; 4 th and 5 th articles the longest and of same length; 4 distal articles with numerous serrated spines of different size, terminal article with robust smooth distal claw.

Legs robust and rather densely spinose; coxae 1 and 3 of about same length; coxa 2 as long as lengths of coxae 1 and 3 together; femur as long as tibia 2, slightly shorter than tibia 1, 3.5 times as long as broad; tibiae 1 and 2 more strongly spinose than femur; tarsus about as long as broad, 1/5 times as long as propodus; propodus feebly curved, 4.5 times as long as broad; sole with about 14 ventral spines, dorsally and laterally only sparsely spinose; main claw robust, distinctly curved, about half length of propodus.

Measurements: Trunk length 2.3; width 1.32 (across 2 nd crurigers); length of abdomen 0.62; length of proboscis 1.42; length of cheliphore 0.21. Lengths of articles of leg 3: coxa 1—0.29; coxa 2—0.56; coxa 3— 0.32; femur 0.96; tibia 1—0.97; tibia 2—1.00; tarsus 0.11; propodus 0.59; main claw 0.26.

Remarks: Up to now no detailled description of A. latipes existed, but the species is easily distinguished from the other Ascorhynchus species in the western Atlantic by its robust build, its straight cheliphore scape and the densely spinose legs. Besides the original description, only Stock (1979: 3, Fig. 1a ) published drawings of the species. The habitus drawing by Stock from Curaçao shows the crurigers farther separated than the Colombian material.

A. latipes appears most closely related to Ascorhynchus corderoi du Bois-Reymond Marcus, 1952 from Brazil, Mauritius and the Aldabra Atoll in the Seychelle Islands. This species is in habitus very similar to A. latipes , but distinctly separated by a two-articled cheliphore scape (cf. du Bois-Reymond Marcus, 1952: 24, Fig.3 ).

The conditions encountered at its sampling locations suggest that A. latipes has few requirements on substrate nature and does not avoid the surf region. Child (1982: 359) assumes "some preference for sand and rocky habitats". In 1979 (p. 16) the same author recorded this species most frequently from the Caribbean coast of Panamá and speaks of a prolonged life cycle.

Distribution: Amphi-atlantic. In the western Atlantic recorded from the Bahama Islands and Florida southwards to the coasts of South America. In the eastern Atlantic the species was found on the coast of Senegal (see Child 1982: 359).

Figures

FIGURE 1. A, External morphology of a pycnogonid, exemplified by Ascorhynchus castelli (Dohrn, 1881) male, after Müller & Roth (1990: 164), slightly modified; abd—abdomen, ch cheliphore, l3 leg 3, lp—cruriger of leg 2, pl—palp, pr—proboscis, ov—oviger; B, proximal part of leg 3 of Anoplodactylus guachaquitae n. sp., male: cd—cement gland duct on dorsal face of femur.

FIGURE 3. Achelia gracilis Verrill, 1900. A, male palp, B, leg 3 of male, C, leg 3 of female, D, cement gland duct, E, tarsus and propodus of male leg 3.

FIGURE 29. Ascorhynchus latipes (Cole, 1906) male only: A dorsal, B lateral, C cheliphore, D palp, E oviger, F foliose spine from article 7, G foliose spines on article 10, H leg 3, I tarsus and propodus of leg 3.