Anoplodactylus micros Bourdillon,1955

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 : 103-105

Anoplodactylus micros Bourdillon,1955

Fig. 55

Anoplodactylus micros Bourdillon,1955: 591 . Stock 1986: 404.

Material: 5.— 6 males (1ov.), 1 fem. (gravid), deposited as follows: 4 males (1 ov.), 1 fem. (gravid) ( SMF 1160 ) ; 1 male ( ZFMK); 1 fem. ( ZSM); coral rubble, 30 m, 18.II.1986 .

12.— 1 male ( ZMA 3361 ), coral rubble, 17–20 m, 7.XII.1985 .

Description of male: Very small, moderately robust species, dorsal outline oval. Segments 3 and 4 fused. Crurigers 1–3 bear a short dorsodistal tubercle with distal seta; the crurigers separated by less than their own diameter. Ocular process as high as diameter, a short tip, eyes distinctly pigmented. Abdomen slender, directed obliquely backwards, slightly higher than ocular process, bearing two short distal setae. Proboscis cylindrical, feebly down-curved; distally somewhat enlarged and bluntly rounded.

Cheliphores moderately robust; scape with a dorsodistal seta, distinctly longer than proboscis; chela rather slender, fingers distinctly curved; cutting edge of immovable finger with 2 pointed teeth, 2 setae on base; cutting edge of movable finger with 3 pointed teeth, one seta on external face. Oviger relatively slender, 6- articled; 3 rd article the longest, 1.4 times as long as 2 nd; 4 th article as long as 5 th and 6 th together; 5 th article with several setae directed proximally; distal article smallest, conical, with 2 proximally-directed setae.

Legs moderately robust and sparsely setose; coxa 1 as long as coxa 3, dorso-laterally with pair of small tubercles each with one seta; coxa 2 1.8 times as long as coxa 1 and coxa 2, with short round ventro-distal genital process on legs 3 and 4; femur and tibiae each with long dorso-distal seta, that on tibia 2 slightly more proximal and on flat tubercle. Femur the longest article, bearing dorso-medial conical cement gland duct at mid-length; tibia 1 just longer than tibia 2; tarsus as long as broad, with 3 slender ventral spines; propodus slender and distinctly curved; strong heel with two robust distal spines and with slender spine on anterior face; sole with small and distally-curved spine on a flat tubercle in proximal third; lamella covering 2/3 of sole and flanked by 2 short setae on each side; main claw robust and feebly curved, its tip reaches to the tip of the spine on anterior margin of heel; auxiliary claw feebly curved, 1/8 length of main claw.

Measurements: Trunk length 0.61; width 0.37 (across 1 st crurigers); length of abdomen 0.17; length of proboscis 0.26; length of cheliphore scape 0.15; length of chela 0.11. Length of articles of leg 3: coxa 1— 0.10; coxa 2—0.18; coxa 3—0.18; femur 0.34; tibia 1—0.30; tibia 2—0.28; tarsus 0.05; propodus 0.24; main claw 0.16; auxiliary claw 0.02.

Female: Similar to male apart from lack of ovigers and cement gland ducts. Leg articles more robust, especially femur; dorso-distal setae on femur and tibia much shorter; sole of propodus without (!) lamella, but with 3 short spines curved distally; heel more slender, distally with one robust spine; auxiliary claws absent.

Remarks: The Colombian material corresponds essentially with the description of Anoplodactylus micros Bourdillon, 1955 from Martinique. Regrettably Bourdillon's description lacks some details, the type material was not available for comparison (originally deposited in the collection of Station marine d'Endoume, Marseille). Stock (1979: 26) provisionally identified a male from Curaçao as A. micros . A re-examination of that specimen showed that it was still immature and not confidently identifiable. There is also considerable doubt about a specimen from Australia, which was classified as A. micros by Stock (1973a: 124). This animal has no distinct teeth on the chela fingers, and the proboscis and the dorsal setae on femur and tibia are considerably shorter than in the original description. The only remarkable difference between the material from the Santa Marta region and Bourdillon's description is the presence of small dorso-distal tubercles on the crurigers 1–3, which is however an easily-missed character, and it is variable with other species in this large genus.

Anoplodactylus micros belongs to a complex of very small and in habitus very similar species, which possess a long dorsodistal seta at least on all tibiae and a long cutting sole lamella. This complex includes Anoplodactylus trispinosus Stock, 1951 from the western Atlantic, A. minutissimus Stock, 1954 from Singapore and A. turbidus Stock, 1975 from the Red Sea, Ethiopia and Madagascar. A. micros is distinguished from A. trispinosus by the toothed chela finger and a shorter cement gland duct, from A. turbidus by a proboscis which bears no ventral setae and a distinctly shorter cement gland duct. A. micros and A. minutissimus both have a similarly-shaped cement gland duct. The trunk segments are all fused in the latter species, the proboscis of A. minutissimus is apparently slenderer than in A, micros . This species has a conical tubercle between origin of proboscis and ovigers, which is absent in A. micros .

Distribution: Martinique and Caribbean coast of Colombia.

Figures

FIGURE 55. Anoplodactylus micros Bourdillon, 1955: A male trunk dorsal, B male trunk lateral, C male proboscis ventral, D male cheliphore, E oviger, F male leg 3, G propodus and tarsus of male leg 3, H cement gland duct, I female leg 3, J propodus and dactlus of female leg 3.