Pigrogromitus timsanus Calman, 1927

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 : 78-79

Pigrogromitus timsanus Calman, 1927

Fig. 41

Pigrogromitus timsanus Calman, 1927: 408 . Child 1979: 46. Child 1982: 367. Staples 1982: 457. Stock 1986: 403. Arnaud 1987: 80. Child 1988: 21. 1988 Nakamura & Child 1988: 667. Stock 1989: 95. Müller 1990: 97. Müller 1990: 74. Nakamura & Child 1990: 304–310.

Material: 1.— 1 male (ov.), 1 fem. (gravid) ( ZFMK), phaeophycean stands on rock, lower mesolittoral, 10.IX.1985 . 3 adults (2 ov.) ( ZMA 3376 ), phaeophycean stands on rock, lower mesolittoral, mainly Sargassum , 9.X.1985 . 1 male (ov.), 2 juv. ( INVEMAR), from Sargassum on rock, mesolittoral, 18.XI.1985 . 1 juv. ( INVEMAR), from Sargassum on rock, mesolittoral 30.XII.1985 .

2.— 10 adults (1 ov.), 24 juv. ( SMF 1485 ), from corallinacean algae on rock, sometimes clinging to anthozoans, ca. 0.5 m, 9.X.1985 .

9.— 1 adult ( SMF 1486 ), under stones, ca. 0–0.5 m, 31.XII.1985 . 1 adult, 7 juv. ( SMF 1487 ), under stones, 0–1 m, 28.I.1986 .

43.— 2 adults (1 ov.) ( SMF 1488 ), Thalassia , 1–1.5 m, 25.II.1986 .

Description of male: trunk oval and robust, all segments free. Crurigers with feebly accentuated round lateral tubercles on their dorso-distal margin; crurigers 1–4 touching each other over entire length, dorsodistally with some short setae. All trunk segments with flatly rounded tubercles in dorso-median line with sparse setae on top. Ocular process broader than high, with rather small, but distinctly pigmented eyes. Oviger origins globular and originating ventro-laterally on trunk, indistinctly separated from 1 st cruriger. Abdomen almost horizontal, twice longer than broad, bearing 4 distal setae. Proboscis a broad cylinder, distally rounded.

Cheliphore slender, scape two-articled, rather slender, distal scape article twice longer than proximal; chela of about same length as distal scape article, proximally with two short setae only; distal region of untoothed chela fingers curved in a characteristic way. Oviger 10-articled, rather robust; 5 th article the longest, a trifle longer than 4 th; 5 distal articles bearing several slender forked spines; the small tenth article with a curved claw.

Legs robust, sparsely setose; coxae 1–3 in all legs of similar length; femur 1.4 times as long as tibia 1 and 2; tarsus as long as broad; propodus feebly curved; sole without heel, with a few sparsely distributed setae only; main claw robust and strongly curved, half length of propodus.

Measurements of male: Trunk length 1.23; width 0.87 (across first or second crurigers); length of abdomen 0.34; length of proboscis 0.58; length of cheliphore scape 0.37; length of chela 0.18; length of leg articles of leg 3: coxa 1—0.22; coxa 2—0.26; coxa 3—0.23; femur 0.46; tibia 1—0.34; tibia 2—0.28; tarsus 0.10; propodus 0.38; main claw 0.17.

Remarks: In the research area Pigrogromitus timsanus colonized the uppermost shallow waters down to 1.5 m only, where it was found among algae. Several specimens were found clinging to small anthozoans and some of them had their proboscides inserted into the oral discs. Apparently these coelenterates are the staple food of P. timsanus . The first author observed the same behaviour in some specimens from Sri Lanka.

The egg mass in ovigerous males is a broad clump, with both ovigers immersed into it. The eggs are numerous and their diameter much smaller than the diameter of an oviger article (cf. Calman 1927: 408, Fig. 104b).

Distribution: The monotypical genus Pigrogromitus is pantropically distributed, in the western Atlantic it is known from Florida (Hedgpeth 1948: 214, Stock 1975: 1015), Curaçao (Stock 1975: 1015; 1989: 95), Panamá ( Child 1979: 47), Belize (Child 1982: 367) and now also from the Caribbean coast of Colombia.

Figures

FIGURE 41. Pigrogromitus timsanus Calman, 1927: A adult lateral, B adult dorsal, C chela, D oviger and enlarged spine, E leg 3.