Thoracophoracarus felix, Gerecke, 2009

Gerecke, Reinhard, 2009, Revisional studies on Thoracophoracarus K. Viets, 1914 (Arachnida, Acari, Hydrachnidia, Arrenuridae), Zoosystema 31 (1), pp. 127-145 : 142-143

Thoracophoracarus (s.s.) felix n. sp. ( Fig. 10 )

TYPE MATERIAL. — Holotype: Madagascar: MD 069, Andohahela (Tulear), Isaka, W stream at the S National Park border (W RIP 118), 200 m, 9.IX.2001, 19.2°C, 0.091 mS/cm, ♂ ( MNHN Ac1124). Paratypes: MD 064, Andohahela (Tulear), Fenoevo, stream at N margin of forest (milky turbid waters), 330 m, 8.IX.2001, 19.4°C, 0.100 mS/cm, 1♀ ( MNHN Ac1125). — MD 039, Andrambovato (Fianarantsoa), spring at left margin of the stream 3 km from the village (upstream from the cascade), 900 m, 20.VIII.2001, 17.3°C, 0.050 mS/cm, 1 ♀ in liquid ( MNHN Ac1126).

MATERIAL EXAMINED. — MD 133, Marofototra (Antalaha, Antsiranana), spring stream 2, right affl. of R. Fandramanana (affl. of MD 132), 120 m, 2.XI.2001, 22.0°C, 0.019 mS/cm, 1 ♂ (coll. Gerecke, Tübingen).

ETYMOLOGY. — This species is dedicated to Felix Rakotondraparany (Antananarivo) who helped us in many different ways during our field work in Madagascar.

DESCRIPTION

Gnathosomal bay broadly V-shaped, a sharply pointed extension of the frontal idiosoma dorsally covering the gnathosoma insertion.Acetabular fields slightly wider than long, with straight anterior and round latero-caudal margins, bearing 60-90 acetabula each. P-2 with 2 or 3 dorsal and 2 mediodistal setae; P-3 with 2 setae, 1 long and fine medioproximally, 1 stronger and shorter laterodistally; P-4 L/H 1.5, equal in H from the base to the tip, with a rather long mediodistal seta; P-5 stout. Male gonopore flanked by a pair of rounded caudal extensions.

Male: idiosoma ( Fig. 10A ) L/W 600-650/490- 540, W Cx-4-tips 535-580, acetabular field L/W 80-110/285-340. Palp ( Fig. 10B ) measurements (L/H): P-1 33-37/35-40, P-2 90-95/70-73, P-3 60-62/55-60, P-4 77-80/48-50, P-5 37-45/20- 25. Leg measurements (L/H): I-L-4 80-85/38-48, I-L-5 85-95/40-45, I-L-6 110-125/32-40; IV-L-4 110-125/35-40, IV-L-5 110/30-40, IV-L-6 110/38. Swimming setae numbers (anterior/posterior):I-L-4 1/0, I-L-5 1/0; IV-L-4 4-5/5-6, IV-L-5 0/3-4.

Female: idiosoma (similar to Figure 7D , differing in acetabular number only) L/W 750/630, W Cx-4-tips 640, gonopore L/W 120/130, genital field W 400, acetabular field W130. Palp measurements (L/H): P-1 30/40, P-2 100/75, P-3 75/65, P-4 90/65, P-5 40/20. Leg measurements (L/H):

I-L-4 85/42, I-L-5 100/42, I-L-6 120/40; IV-L-4 140/40, IV-L-5 130/38 IV-L-6 117/30. Swimming setae numbers (anterior/posterior): I-L-4 1/0, I-L-5 2/0; IV-L-4 4/5, IV-L-5 0/4.

REMARKS

Thoracophoracarus felix n. sp. is similar to T. cooki n. sp. in the V-shaped gnathosomal bay, acetabular fields little wider than long, P-2 with only 2 mediodistal setae and stout P-5. It differs from that species in lower acetabula numbers (less than 100 + 100), a slightly more slender P-4 and the step-like extensions in the male genital area more narrow. Due to some minor differences, the specimen from site 133 is attributed questionably to this species. The extension covering the dorsal insertion of gnathosoma is right-, not acute-angled, and the step-like caudal projections are larger and more prominent laterally than in the middle. Better knowledge about individual variability is needed in order to understand the significance of such differences. The large geographic distance between site 133 (in the north of Madagascar) and the southern collecting sites of T. felix n. sp. would explain a taxonomic difference between these populations.

Figures

FIG. 10. — Thoracophoracarus felix n. sp., holotype ♂ (MNHN Ac1124): A, ventral idiosoma; B, palp. Scale bars: 100 μm.

FIG. 7. — Thoracophoracarus cooki n. sp.: A-C, paratype ♂ (MNHN Ac1119); A, dorsal idiosoma; B, ventral idiosoma; C, palp; D, paratype ♀ (MNHN Ac1120), ventral idiosoma. Scale bars: 100 μm.