Anoplodactylus monotrema Stock, 1979

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 : 105-107

Anoplodactylus monotrema Stock, 1979

Fig. 56

Anoplodactylus monotrema Stock, 1979: 15 . Child 1979: 56. Child 1982: 372. Stock 1986: 404. Müller 1990: 284.

Material: 4.— 1 male, 1 fem., 2 juv. ( ZFMK), algal stands on rock, mesolittoral, 24.V.1985 .

8.— 1 male ( MNHN), poriferans and hydroids on shaded jetty piles, 0–1 m, 14.V.1985 .

9.— 2 juv. ( SMF 1318 ), under stones, 0-0.5 m, 31.XII.1985 .

10.— 1 fem. ( SMF 1313 ), algal stands on rock, lower mesolittoral, 7.V.1985 . 1 fem. (gravid) ( SMF 1308 ), same locality, 10.V.1985. 1 male, 2 juv. ( INVEMAR) , algal stands on rock, lower mesolittoral, 12.V.1985. 1 fem. (gravid) ( SMF 1297 ), Sargassum on rock, mesolittoral, 31.VIII.1985 .

12.— 1 male ( ZSM), on hydroids and octocorallians, 16–18 m, 16.IX.1985 . 1 fem. (gravid) ( SMF 1298 ), coral rubble, 16–18 m, 16.IX.1985 . 1 male, 2 fem. ( ZMA 3362 ), coral rubble, 18 m, 2.X.1985 .

15.— 1 male ( SMF 1312 ), algal stands on rock, 5–7 m, 22.V.1985 .

16.— 8 males (3 ov.), 3 fem. (2 gravid), 5 juv. ( SMF 1295 ), algal stands on rock, mesolittoral, 22.V.1985 . 1 fem. (gravid) ( SMF 1300 ), red and brown algae on rock, mesolittoral, 15.VII.1985 . 1 male (ov.) ( USNM), brown algae, mesolittoral, 12.II.1986 .

17.— 1 fem. (gravid) ( SMF 1309 ), on Cnidoscyphus among stone blocks, lower mesolittoral, 27.VI.1985. 1 juv. ( SMF 1316 ) , same locality, 15.VII.1985 .

19.— 1 fem. ( SMF 1319 ), Thalassia , 5l Substrat, 0.5–4 m, 8.XI.1985. 1 male, 1 juv. ( SMF 1314 ) , same locality, 3.III.1986 .

20.— 1 fem. (gravid) ( SMF 1304 ), on Sargassum cymosum , 5 l of substratum, mesolittoral- 0.5 m, 3.III.1986 .

21.— 2 males (1 ov.), 1 fem. (gravid), 2 juv. ( SMF 1306 ), on Digenia simplex , 5 l of substratum, mesolittoral, 27.VI.1985 . 1 male, 1 fem. (gravid) ( SMF 1296 ), on Digenia simplex , 5 l of substratum, mesolittoral, 8.VII.1985 . 1 male (ov.), 2 fem. (gravid), 4 juv. ( SMF 1302 ), on Digenia simplex , 5 l of substratum, mesolittoral, 8.XI.1985 . 1 juv. ( SMF 1310 ), on Digenia simplex , 5 l of substratum, mesolittoral, 12.II.1986 . 1 male ( SMF 1320 ), on Digenia simplex , 5 l of substratum, mesolittoral, 3.III.1986 .

24.— 1 male ( ZSM), Thalassia , 0.51 m, 8.IX.1985 .

27.— 1 fem. (gravid) ( SMF 1305 ), coral rubble, 7–8 m, 27.IX.1985 .

28.— 1 fem. ( SMF 1315 ), under stones, 0.5 m, 4.IV.1986 .

31.— 1 male (ov.), 1 fem. (gravid) ( SMF 1301 ), from brown and red algae on rock, mesolittoral, 9.IV.1986 .

32.— 1 fem. (gravid) ( SMF 1307 ), from brown algae, mesolittoral, 3.VIII.1985 .

33.— 1 male ( SMF 1311 ), Thalassia , 0–1 m, 5.VIII.1985 .

34.— 1 fem., 1 juv. ( SMF 1321 ), under stones, 0.5 m, 10.IV.1986 .

37.— 1 fem., 1 juv. ( SMF 1317 ), from detritus, algae and hydroids, 6 m, 4.VI.1985 .

39.— 2 males (1 ov.), 3 fem. (1 gravid), 6 juv. ( SMF 1303 ), from algae growing on rock, mesolittoral, 27.V.1985 .

45.— 2 fem. (gravid), 1 juv. ( SMF 1299 ), from algae, hydroids and bryozoans on rock, 6–10 m, 25.IX.1985 .

Description of male: Trunk robust, oval in dorsal outline, segments 3 and 4 fused or indistinctly separated. Crurigers as long as broad, separated by 1/4–1/5 of their diameter, without any tubercles, each with a short dorsal seta. Ocular process lower than basal diameter, broadly rounded. Eyes large and darkly pigmented. Abdomen short, directed obliquely backwards, about conical with a rounded tip, distally bearing 3–4 short setae. Probosics very robust, cylindrical, proximally slightly curved and distally obtuse.

Cheliphores moderately robust, scape distinctly longer than proboscis; chela with distinctly curved fingers, each cutting edge with 3 pointed teeth. Oviger 5-articled; 3 rd article the longest, 1.7 times as long as 2 nd; terminal article barely shorter than fifth, with about 9 short spines which are directed proximally.

Legs robust, sparsely setose; coxa 1 of almost same length as coxa 3, lacking tubercles; coxa 2 the longest coxal article, 1.4 times as long as coxa 1; femur the longest and most robust article; cement gland duct with a long oval pore, in dorso-median line near end of proximal half of femur length, sunken slightly in its dorsal suface; tibia 1 is1.3 times as long as tibia 2; tarsus as long as broad; propodus feebly curved, with a flat heel armed with 2 robust and 2 slender spines; sole with 6 short spines curved distalwards, flanked by 5 short setae on both sides; no propodal lamella; main claw robust and feebly curved, its tip not reaching slender spines on distal margin of heel; auxiliary claw 1/8 length of main claw.

Legs from coxa 2 to tibia 2 frequently greenish, rest of animal yellowish-white; distal half of proboscis often tinged with brownish.

Measurements: Trunk length 0.59; width 0.45 (across first crurigers); length of abdomen 0.18; length of proboscis 0.31; length of cheliphore scape 0.23; length of chela 0.15; length of articles of leg 3: coxa 1—0.13; coxa 2—0.18; coxa 3—0.14; femur 0.40; tibia 1, 0.37, tibia 2, 0.28; tarsus 0.08; propodus 0.31; main claw 0.20; auxiliary claw 0.02.

Female: like male other than the sex-specific characters.

Postlarva: Legs 4 just stumps, without articulation, shorter than abdomen. Total length 0.35.

Remarks: Anoplodactylus monotrema is closely related to Anoplodactylus robustus (Dohrn, 1881) from the eastern Atlantic and the European Mediterranean and to Anoplodactylus virescens (Hodge, 1864) from the same region. For a long time A. monotrema was confounded with A. robustus . Stock (1979: 15) recognized that material from the American east coast represented a full species. While in A. robustus all trunk segments are fused and the first coxae bear small dorso-distal tubercles, the first coxae in A. monotrema are always plain, only segments 3 and 4 fused. In A. robustus the male femur bears 3–6 cement gland pores, whereas in A. monotrema there is only a single larger, long oval cement gland opening. Another difference is that the cutting edges of the chela fingers are untoothed in robustus . A. virescens is differentiated from A. monotrema by untoothed chela fingers and the possession of 3–6 cement gland pores on each femur.

The species is frequent in the Santa Marta region and does not prefer any substratum, having been collected on all substrata defined in the introduction. It was found most often from the uppermost shallow waters to a maximal depth of 18 m. Only 7 ovigerous males were taken in the months I, V and VI, females bore eggs in their ovaries in months III, V–IX and XI.

Distribution: Numerous records in the western Atlantic from Florida southwards to Brazil; a compilation of distribution regions is given in Stock (1986: 404). The species was not recorded from Colombia previously.

Figures

FIGURE 56. Anoplodactylus monotrema Stock, 1979: A male trunk dorsal, arrow to seta on lateral process, B male trunk lateral, C male proboscis ventral, D postlarva dorsal, E postlarva ventral, F chela, G oviger, H male leg 3, I propodus and tarsus of leg 3, J cement gland pore lateral, K cement gland pore from dorsal.