Nymphon floridanum Hedgpeth, 1948

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 : 83-85

Nymphon floridanum Hedgpeth, 1948

Fig. 45–46

Nymphon floridanum Hedgpeth, 1948: 196 . Child 1979: 37, (literature). Child 1982: 374. Stock 1986: 402.

Material: 4.— 2 males (ov.), 1 juv. ( ZMA 3373 ), coral rubble, 25 m, 18.IX. 1985 . 1 male (ov.), 1 adult lacking legs, 2 juv. ( SMF 1515 ), coral rubble, 18 m, 9.X.1985 . 1 male, 2 fem. (1 gravid), 2 juv. ( SMF 1516 ), coral rubble, 30 m, 10.III.1986 .

5.— 1 fem., 1 juv. ( SMF 1517 ), coral rubble, 30 m, 18.II.1986 . 1 male ( ZSM), coral rubble, 13 m, 3.VI.1985 .

9.—1 fem. ( INVEMAR), on detritus and hydroids on stones, 22–23 m, 19. VI.1985. 1 juv. ( SMF 1518 ), on detritus and hydroids on stones, 25–27 m, 22.VI.1985 . 2 males (1 ov.), 3 fem. (1 gravid) ( SMF 1519 ), coral rubble, 30 m, 21.IX.1985 . 1 juv. ( SMF 1520 ), coral rubble, 12–15 m, 15.XII.1985 . 1 juv. ( SMF 1521 ), coral rubble, 18 m, 18.XII.1985 . 1 fem., 2 juv. ( ZFMK), same locality, 16 m, 2.I.1986 . 1 male, 1 adult lacking legs, 1 juv. ( SMF 1522 ), coral rubble with hydroid growth, 30 m, 10.II.1986 .

12.— 3 fem. ( SMF 1523 ), coral rubble, 16–18 m, 16.IX.1985. 1 adult lacking legs ( MNHN), coral rubble, 18 m, 2.X.1985. 1 male ( SMF 1524 ) , coral rubble, 17–20 m, 7.XII. 1985.

13.— 1 male, 1 adult lacking legs ( ZSM), coral rubble, 21 m, 8.XI.1985 .

Description of male and female: Dorsal trunk outline a long oval, all segments free. Crurigers smooth, without setae or tubercles, length and diameter nearly equal, separated by their own diameter. Ocular process barely higher than basal diameter, distally pointed, eyes feebly pigmented. Neck region variable, proximally slender or more robust, but not longer than both first trunk segments (1+2). Lateral oviger origins not differentiated from first crurigers. Abdomen a short lappet, as long as its diameter, distally rounded. Proboscis cylindrical, 2.5 times as long as broad, slightly narrower in its distal sixth.

Cheliphores slender, scape distally reaching proboscis tip; hand of chela as long as fingers, which bear some short setae at base; fingers feebly curved and tips crossing, cutting edge with 16 teeth on immovable and 13 on movable finger, all bicuspid. Palp slender, second and third articles of same length, longer than other articles; distal article just slightly shorter than second and third articles, but 4.5 times as long as fourth article; distal two articles with numerous slender setae, which are mostly twice as long as the diameter of these articles. Oviger 10-articled, the lengths of the articles increasing from first to fifth, then decreasing, but the four distal articles subequal in length; 5 th article elongate and slightly enlarged in distal fourth, on ventral face with a row of sparse setae all along its length; 6 th article 1/3 the length of fifth, slightly curved, bearing numerous setae longer than the diameter of article on both sides; the 4 distal articles bearing serrated spines, formula 9:7:6:7 (figured male); terminal claw very slender, curved and smooth, barely longer than terminal article.

Legs very long and slender; coxa 2 nearly three times as long as coxa 1 and coxa 3; femur and tibia 1 subequal in length, sparsely setose, tibia 2 is 1.4 times as long as tibia 1 or femur, densely setose on ventral and dorsal sides; tarsus twice as long as broad, propodus feebly curved, 7 times as long as broad; sole without heel, distal two thirds bearing 5 slender spines and several setae; main claw moderately curved, 0.35 times length of propodus, proximal inner margin with very small denticles; auxiliary claw barely longer than main claw, its proximal inner margin also denticulated.

Measurements of male: Trunk length 1.07; width 0.47 (across first crurigers); length of abdomen 0.14; length of probscis 0.57; length of cheliphore scape 0.46; length of chela 0.50; lengths of leg articles: coxa 1— 0.32; coxa 2—0.93; coxa 3—0.39; length of femur 1.86; length of tibia 1—1.88; length of tibia 2—2.79; length of tarsus 0.21; length of propodus 0.60.

Remarks: Nymphon floridanum is the nearest relative of Nymphon setipedes Child, 1988 from Belize, with which it shares the slender build and the bicuspid teeth of the chela fingers. Nymphon setipedes differs from N. floridanum by an elongated neck region, which exceeds the length of the adjoining two trunk segments (1 st and 2 nd). In contrast the cheliphores of N. setipedes are more robust. The length of the neck region in N. floridanum , the number of teeth on the cutting edges of chela fingers, as well as the number of serrated spines on the distal oviger articles are variable. The Colombian animals differ from the re-description by Stock (1975a: 994), as their propodal sole has 5 slender spines, which are partly hidden by the lateral setae.

While the species has been frequently collected since its original description, data on colonized substrata are rare and heterogenous. Hedgpeth (1948: 166) mentioned a specimen from drifting algae, Stock (1975a: 994) records Thalassia , Halimeda , poriferans, calcareous sand, sand and bottoms with a mix of sand and mud. Child (1979: 37) recorded 3 specimens from a fouling panel with epizoans, Child (1982: 374) a single juv. from Halimeda .

In the Santa Marta region the colonized substratum was fairly homogenous and consisted almost exclusively of coral rubble, normally covered by varying amounts of detritus, also in places covered by hydroids and bryozoans. Mature individuals were found all year round, but the four ovigerous males were collected during the rainy season only. The vertical distribution agrees with records in the literature. N. floridanum avoids the surf zone and has been recorded at depths between 1–402 m (cf. Stock 1986: 402).

Distribution: Tropical and sub-tropical west-ern Atlantic. Recorded from Georgia, Florida, Gulf of Mexico, Belize, Panamá, Caribbean Antilleans, Bahama Islands and Yucatán Channel (cf. Child 1979: 37; 1982: 374; Stock 1986: 402).

Figures

FIGURE 45. Nymphon floridanum Hedgpeth, 1948, male: A oviger, B four terminal articles of oviger, foliose spines and end claw.

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.