Macroxenodes aff. amazonicus Ishii, Nguyen Duy-Jacquemin & Condé, 1999

Duy-Jacquemin, Monique Nguyen, 2002, New species and distribution of the genera Lophoturus and Ancistroxenus (Myriapoda, Diplopoda, Penicillata) in the Caribbean and northern South America, Zoosystema 24 (2), pp. 451-470 : 467-468

Macroxenodes aff. amazonicus Ishii, Nguyen Duy-Jacquemin & Condé, 1999

( Fig. 6 )

MATERIAL EXAMINED. — Tobago. Castara Bay, under bark of live tree, 9. VII.1999, 1 10 p. l. — Man of War Bay, North of Charlotteville, track to Pigeon Peak, under bark of live tree, 11. VII.1999, M. Judson leg., 2 ind. 8 p. l. (only one described), 1 ind. 6 p. l.

DESCRIPTION

Stadium VI (female with 10 pairs of legs)

Measurements. Body length (without caudal pencil) 1.85 mm. Tarsus II length of 10 th leg 95 µm.

Head. Posterior tufts with anterior row of 12 and posterior row of eight trichomes. Surface of labrum covered with numerous, small, cuticular setae and two anterior rows of granules; anteromedian margin of labrum with 6 + 1 + 5lamellar fingers. Clypeo-labrum with 10 setae along posterior margin.

Each outer palpus of gnathochilarium with 15 sensilla basiconica pseudo-segmented at apex, each inner palpus with 22 sensilla.

Trunk. Position of trichomes as in M. amazonicus , with maximum number of trichomes (73) on tergite IV; lateral protuberance of collum with four and five trichomes.

Stadium V (one larva with eight pairs of legs)

Measurements. Body length (without caudal pencil) 1.40 mm. Tarsus II length of 8 th leg 85 µm.

Head. Posterior tufts with anterior row of 10 and posterior row of seven and eight trichomes. Surface of labrum as in larva VI, but with 4 + 1 + 4lamellar fingers. Clypeo-labrum with eight setae along posterior margin.

Each outer palpus of gnathochilarium with 15 sensilla basiconica, each inner palpus with 21 sensilla.

Trunk. Forty four to 46 trichomes on tergite II to IV; lateral protuberance of collum with three and four trichomes.

Stadium IV (one larva with six pairs of legs) Measurements. Body length (without caudal pencil) 1.25 mm. Tarsus II length of 6 th leg 78 µm.

Head. Posterior tufts with anterior row of eight and 10 trichomes; posterior row of seven and eight trichomes. Surface of labrum as larva VI, but with 4 + 4 lamellar fingers. Clypeo-labrum with nine setae along posterior margin.

Each outer palpus of gnathochilarium with 13 sensilla basiconica, each inner palpus with 21 sensilla.

Trunk. Forty two to 45 trichomes on tergite II to V; each lateral protuberance of collum with five trichomes.

REMARKS

As in M. amazonicus from Brazil vicinity of Manaus, antennal article VI has a dorsal group composed of three sensilla basiconica a, i, p, one setiform sensilla s between a and i, one sensillum coeloconicum c posterior to p. However, in contrast to typical M. amazonicus , the posterior sensillum p is thinner than i and additional thin sensilla are present: one or two ( Fig. 6D ) in stadium IV, three or four in stadium V. In the right antenna of larva VI, the separation between the dorsal and postero-ventral groups of antennal sensilla is not evident ( Fig. 6B ), unlike the holotype of Macroxenodes amazonicus ( Fig. 6E ). These larvae clearly differ from the Macroxenus sp. from near Manaus ( Ishii et al. 1999), which has numerous sensilla arranged in one or two rows and a different arrangement of trichome areas on the tergites. Macroxenodes is one of three genera of Polyxenidae (with Macroxenus Brölemann, 1917 and Chilexenus Silvestri, 1948 ) with the gnathochilarial sensilla basiconica showing a pseudo-segmentation at apex.

Figures

FIG. 6. — A-C, Macroxenodes aff. amazonicus Ishii, Nguyen Duy-Jacquemin & Condé, 1999, larva 10 p.l. from Tobago; A, sensilla on left antennal article VI; B, C, sensilla on right antennal articles VI and VII; D, larva 6 p.l. from Tobago, sensilla on left antennal antepenultimate article; E, Macroxenodes amazonicus Ishii, Nguyen Duy-Jacquemin & Condé, 1999, holotype, sensilla on antennal article VI (after Ishii et al. 1999: 267, fig 87). Abbreviations: a, anterior sensillum basiconicum; c, sensillum coeloconicum; i, p, intermediate and posterior sensilla basiconica; s, setiform sensillum. Scale bars: 25 µm.