Anoplodactylus bahamensis Child, 1977

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 : 86-88

Anoplodactylus bahamensis Child, 1977

Fig. 46

Anoplodactylus bahamensis Child, 1977: 587 . Child 1982: 368. Stock 1986: 403.

Material: 24.— 1 male (ov.), 2 fem. (gravid) ( SMF 1241 ), Thalassia , 1 m, 4.IX.1985 .

27.— 1 male ( ZSM), coral rubble among Thalassia , 1 m, 1.XI.1985 .

29.— 1 male, 3 fem. (gravid) ( SMF 1242 ), Thalassia , 1–2 m, 21.I.1986 .

30.— 1 male, 1 fem. (gravid), 6 juv. ( INVEMAR), Thalassia , 2 m, 29.V.1985 . 9 males (2 ov.), 9 fem. (7 gravid) ( SMF 1243 ), Thalassia , 6.VI.1985 . 6 males (5 ov.), 3 fem. (gravid), 2 juv. ( SMF 1244 ), Thalassia , 19.VI.1985 . 28 males (6 ov.), 8 fem. (gravid) ( SMF 1245 ), Thalassia , 4.VII.1985 . 1 male, 4 fem. (3 gravid) ( MNHN), Thalassia , 6.VIII.1985 . 1 fem. (gravid), 1 juv. ( SMF 1246 ), Thalassia , 0.5–2 m, 11.IX.1985 . 2 males (1 ov.) ( SMF1247 ), Thalassia , 2–3 m, 4.XII.1985 . 10 males (4 ov.), 7 fem. (4 gravid), 22 juv. ( SMF 1248 ), Thalassia , 1–2 m, 17.I.1986 . 4 males, 7 fem. (5 gravid), 4 juv. ( ZFMK), Thalassia , 1–3 m, 24.I.1986 . 1 male, 2 fem., 1 juv. ( SMF 1249 ), Thalassia , 1–2 m, 9.II.1986 .

33.— 1 male (ov.) ( SMF 1251 ), Thalassia , 0.5 m, 14.XI.1985 . 1 fem. (gravid) ( SMF 1252 ), same locality, 20.XII.1985 .

34.— 3 fem. (2 gravid) ( SMF 1253 ), under stones in ca. 0.5 m, 10.IV.1986 .

37.— 1 male (ov.) ( SMF 1254 ), on detritus, algae and hydroids, 6 m, 4.VI.1985 .

38.— 4 males (2 ov.), 6 fem. (4 gravid), 1 juv. ( ZMA 3375 ), Thalassia , 0.5 m, 17.III.1986 .

39.— 1 male ( USNM), under stones, lower mesolittoral, 14.IV.1986 .

40.— 1 male ( SMF 1255 ), Thalassia , 1–3.5 m, 8.VIII.1985 . 1 juv. ( SMF 1256 ), Thalassia , 1–3 m, 3.IX.1985 . 1 fem. (gravid) ( SMF 1257 ), Thalassia , 2–4 m, 28.X.1985 .

43.— 43 males (24 ov.), 23 fem. (19 gravid), 7 juv. ( SMF 1258 ), Thalassia , 1–1.5 m, 25.II.1986 .

44.— 4 males (2 ov.), 3 fem. ( ZSM), Syringodium , 1.5–2 m, 25.II.1986 .

45.— 1 juv. ( SMF 1259 ), from algae, hydroids and bryozoans on rock, 6–10 m, 25.IX.1985 .

Description of male: Trunk in dorsal view oval, third and fourth segments fused. Crurigers 1–3 each bearing a flat dorso-distal tubercle with a short apical seta; fourth cruriger in most cases without this tubercle, but often with the dorso-distal seta; crurigers separated by 1/2 of their diameter, decreasing in length from process 1–4. Ocular process twice higher than its basal diameter, eyes large and well pigmented. Abdomen longer than ocular process, length three times as long as diameter at base, nearly erect and distally bearing 6 short setae. Proboscis a prolonged cylinder, twice as long as broad, sometimes slightly more slender, ventrally and ventrolaterally with some short setae.

Cheliphores long and slender, scape slender and scarcely longer than tip of proboscis, with some short setae; both fingers rather strongly curved; the immovable one shorter and most often with 2 pointed teeth, the movable one longer and most often with 3 such teeth. Oviger in male 6-articled; 3 rd article the longest, about 1.4 times as long as second; 4 th article about as long as 5 th and 6 th together, slightly curved; terminal article considerably more slender and measuring 1/3 of length of 5 th article; terminal and subterminal articles with some sparse setae, which are short and directed towards their base.

Legs rather robust; coxa 1 and coxa 3 of similar length, i. e. half the length of coxa 3; femur the longest leg article, with a tiny dorso-distal tubercle with longish straight seta; cement gland duct in a dorso-distal position at about middle of femur, short and cap-like with a broad distal opening; tibiae each with a long dorso-distal seta, which on tibia 2 is in slightly less distal position; tarsus as long as broad; propodus with a very distinct heel, at almost right angle with the sole, this heel clad with two robust distal spines and two much more slender spines on the anterior side; sole with 4 small slender spines in proximal row, distal two thirds with a long cutting lamella; main claw robust and almost straight, not reaching the distal margin of heel; auxiliary claw slightly curved and of 1/6 length of main claw.

Measurements: Trunk length 0.65; width 0.44 (across first crurigers); length of abdomen 0.21; length of proboscis 0.33; length of cheliphore scape 0.23; length of chela 0.13. Lengths of leg 3: coxa 1—0.10; coxa 2—0.23; coxa 3—0.12; length of femur 0.42; length of tibia 1—0.38; length of tibia 2—0.34; length of tarsus 0.06; length of propodus 0.25; length of main claw 0.17; length of auxiliary claw 0.03.

Female: Neglecting the sex specific characters like male.

Postlarva: with stumps of the forming leg 4, without apparent articulation lines, total length 0.5.

Remarks: As stated by Child (1977b: 587), A. bahamensis appears related to Anoplodactylus spinirostrum Stock, 1973 , from the South-East of Australia and with Anoplodactylus turbidus Stock, 1975 from the Red Sea and the Dahlak Archipelago of Ethiopia in the north-western Indian Ocean. All these species have a similar aspect with a ventrally setose proboscis, a pronounced heel and a long lamella on the propodus. Nearer relationships may be assumed to A. spinirostrum , which differs from A. bahamensis by a more robust and ventrally more setose proboscis, the chela fingers are less toothed, the cement gland duct is more slender and auxiliary claws are absent. The development of dorso-distal tubercles on the crurigers, as well as form and number of teeth on the chela fingers shows a certain amount of variability (compare fig. 46 and Child 1977b: 587, Fig. 2 ).

Although many females in the genus Anoplodactylus (as they lack the male characters of ovigers and cement glands) cannot be identified with certainty, those of A. bahamensis may be easily distinguished in Colombian material by their ventral setose proboscis combined with toothed chela fingers from even syntopical females of Anoplodactylus trispinosus Stock, 1951 .

Although only 3 specimens of A. bahamensis were known from literature before in the Santa Marta region the species was commonly collected. Almost all samples came from sea-grass meadows, mostly Thalassia . The species evidently prefers the upper sublittoral and avoids the surf area. Including the data from the literature the vertical distribution ranges from 0.5 to 12 m depth. Ovigerous males were collected all year round except in the months IV–V, VIII and X. Ovaries of females of at least a number of specimens contained distinct eggs except in month XI.

Distribution: Bahamas (Child 1977: 587), Belize (Child 1982: 368) and Caribbean coast of Colombia.

Figures

FIGURE 2. Achelia gracilis Verrill, 1900. A, male dorsal, B, female dorsal, C, male lateral, D, male cheliphore, E, female oviger, F, male oviger. Scale 200 mm for A–C, 50 mm for D–E, 100 mm for F.

FIGURE 46. Anoplodactylus bahamensis Child, 1977, male (except E): A trunk dorsal, B trunk lateral, C proboscis ventral, D another proboscis ventral, E postlarva dorsal, F chela, G chela of comparative specimen from USNM, H terminal articles of oviger, I leg 3, J propodus and tarsus, terminal and auxiliary claw, cutting lamella, K cement gland duct.