Acumontia succinea, Mendes, Amanda C. & Kury, Adriano B., 2012

Mendes, Amanda C. & Kury, Adriano B., 2012, Notes on the systematics of the Triaenonychinae from Madagascar with description of a new species of Acumontia Loman (Opiliones: Laniatores), Zootaxa 3593, pp. 40-58 : 48-55

Acumontia succinea sp. nov.

( Figs. 6–12 )

Type data. USNM Male (3) Holotype, 4 3 and 5 Ƥ paratypes. MADAGASCAR, Antsiranana, P.N. Mt. D'Ambre, Montagne d'Ambre, 1100m, 12.32S 49.10E, 23–28.XI.1993, Coddington, J., Scharff, N., Larcher, S., Griswold, C., Andriamasimanana, R. col. (CG.24.LUN.0); 5 3 6 Ƥ paratypes, same data, (SL.25.LUN.); 2 Ƥ paratypes, same data, (CG.27.LUN.); 3 3 2 Ƥ paratypes, same data. (SL.27.LUN.); 4 3 3 Ƥ paratypes, same data, (CG.26.LDN2.); 1 Ƥ paratype, same data. (SL.26.BED.); 4 3 3 Ƥ paratypes, same data, (RA.26.LDN.); 9 3 6 Ƥ paratypes, same data. (NS. 27.GEN.); 1 juv. paratype, same data, (CG.27. NEW 2). MNRJ 0 7581, 4 3 5 Ƥ paratypes, same data, (SL.26.LUN2.).

Distribution. Known only from the type locality in WWF Ecoregion AT0118 ( Madagascar subhumid forests), WWF 01- type formation (Tropical & Subtropical Moist Broadleaf Forests). Most Malagasy Triaenonychini are endemic to one of the two WWF 01- type formations that run roughly in a North-South direction making 2 long stripes in the Eastern half of the island (See Figs. 12 –14). Only one species ( Decarynella gracilipes ) occurs in the 02- type formation (Tropical & Subtropical Dry Broadleaf Forests). No species is known from the two 13- type formations (Deserts & Xeric Shrublands). Lawrence (1959: 60) recorded two females of Acumontia lomani (= A. armata ) from Montagne d'Ambre. However, as this species is distributed in Central-eastern and Southern Madagascar, except for those two females, probably it is a misidentification. Those two females could be A. succinea sp. nov. The remaining old record from Montagne d’Ambre is from Hovanuncia monticola Lawrence, 1959 , quite different from the species of Acumontia (see Discussion).

Etymology. Species name is a Latin adjective meaning “from amber”, in reference to the locality where the types were collected, the Parc national de la Montagne d'Ambre.

Diagnosis. Differs from other species of Acumontia (except for A. hispida , A. horrida and A. remyi ) by having four and three tarsomeres on leg I on males and females respectively. Differs from A. hispida and A. horrida by the apophysis of ocularium unbranched. Similar to Acumontia majori , A. longipes , A. remyi , and A. roberti but differing by the number of tarsomeres on leg I. Additionally, differs from A. majori and A. roberti by having the spines of area III less inclined backwards, tubercles of free tergites high and thin, and trochanter of pedipalp with one pointed tubercle on the dorsum. From A. longipes by the leg II about three times the body (instead of five times), and by the size of tubercles of area II in relation to the ones of area III (much smaller). From A. remyi for the absence of pairs of spines on free tergites I–III.

Description of male holotype. Measurements: Carapace: length 1.8 maximum width 2.8; Abdominal scutum length 3.2, maximum width 3.7; Appendages measurements as in Table 1 .

Dorsal scutum and free tergites: Scutum outline asymmetrical hourglass-shaped, typical of the family ( Figs 6 A, 7A). Tegument with microsculpture, with scaly aspect in some parts (lateral area, anterior and posterior margins of scutum), covered by pustules ( Fig. 7 ). Anterior margin of carapace with a row of six setiferous tubercles, the outermost two larger than the four internal ( Figs. 6 A, 7A, B, D). Ocularium elevated, conical, bearing an apical, long, spiniform apophysis ( Figs 6 , 7 ). Eyes located high, far from base of ocularium ( Figs 6 B, 7B, D). Carapace and areas marked only by inconspicuous faint grooves ( Fig. 7 D). Area I with a pair of paramedian tubercles larger than the common granules (pustules) that cover the body, area II with a pair of larger paramedian tubercles similarly sized to the tubercles of the anterior margin of carapace, with two small acuminate tubercles lateral to them, area III with pair of spines twice as large the tubercles of area II, but smaller than the apophysis of the ocularium, slightly bent backwards ( Figs. 6 , 7 ). One transverse row of setiferous tubercles in posterior margin and free tergites I–III, larger in free tergites II and III ( Figs. 6 , 7 A–C). Dorsal anal operculum with rounded tubercles ( Fig. 7 C).

Chelicerae ( Figs. 6 A, 8A, B): Not sexually dimorphic, with an apical setiferous spiniform tubercle on basal segment.

Pedipalps ( Figs 8 C, D): Trochanter with one ventral high setiferous acuminate tubercle and a dorsal setiferous acuminate tubercle. Femur robust, bearing a ventral row of four high setiferous tubercles, the two basal divergent and larger than the two distal; dorsal row of four high setiferous tubercles; two mesal subdistal setiferous tubercles. Patella with two mesal subdistal setiferous tubercles. Tibia with three mesal and three ectal setiferous tubercles. Tarsus with four mesal and four ectal setiferous tubercles. All tubercles of pedipalps bear subdistal setae, not apical.

Legs: All legs covered with small setiferous tubercles. Coxa I with tegument covered with small pustules ( Figs. 9 A–C), armed ventrally with an anterior row of setiferous stout tubercles, the two most external fused together; other tubercles smaller and bearing apical setae ( Figs. 9 A, B). Femur I covered by small setiferous tubercles, with three ventral basal larger setiferous tubercles ( Fig. 10 A). Metatarsus I with calcaneus notched and much shorter than astragalus ( Figs. 10 A–C). Coxa II with dorsal apophyses and stout retrolateral setiferous tubercles ( Fig. 7 B). Coxa IV with three dorsal setiferous tubercles, one apical large, and two prolateral ( Figs 7 A, B). Trochanter IV with one distal dorsal apophysis and some tubercles ( Fig. 7 A). Tarsal counts of legs I–IV: 4(2)/ 11(3)/4/4 (paratype used for SEM); 4/4(2), 11/13(2), 4/4, 4/4 (holotype).

Color (in alcohol) ( Fig. 6 ). Body and appendages Brownish Orange (54), legs, chelicerae and pedipalps loosely and small honeycomb-reticulated in Dark Brown (59). Patches of Dark Brown (59) on the following: anterior rim of carapace; on and around the ocularium spreading in wide honeycomb-pattern; mid portion of scutal areas, including the main paired spines; a pair of elongate tongues running from posterior edges of carapace along laterals of mesotergum down to posterior corners of abdominal scutum. Posterior half of free tergite I and all free tergites II–III Dark Brown (59).

Genitalia: Ventral setiferous plate deeply cleft, dividing the plate into two halves, three pairs of ventral and one pair of dorso-marginal straight setae ( Figs. 11 C–E). Dorso-lateral plates ear-shaped, reaching half the complex of glans ( Figs. 11 A–C, E). Complex of stylus long, stylus thin and sinuous, with a ventral foliaceus ( Fig. 11 F) and a dorsal multi-pointed process ( Fig. 11 G). Complex of glans with a pair of lateral winglets ( Figs. 11 A–E).

Variation: Middle pair of tubercles of area II with lateral rounded tubercles (not spiniform like in the holotype). Sometimes two of the three dorsal tubercles in coxa IV are fused. Tarsal counts of legs I–IV in males 4(2)/10-12(3)/ 4/4.

Measurements: Males (n=5), carapace length 1.6–1.8, maximum width 2.8–3.3; abdominal scutum length 3.2–3.7, maximum width 3.6–4.7; Femur I 2.3–2.8, II 3.7–4.5, III 2.4–3.2, IV 3.6–4.2. Females (n=5), carapace length 1.6–1.8, maximum width 2.7–2.8; abdominal scutum length 2.4–4.1, maximum width 3.8–4.1; Femur I 2.1–2.6, II 3.4–4.0, III 2.5–3.2, IV 3.2–3.8.

Female. Identical to males in relation to the dorsal scutum armature. They lack the ventral notch on metatarsi I, body smaller and legs I and II with lower tarsal counts than males: 3(2)/8-10(3)/4/4.

Juvenile. Carapace length 1.8, maximal width 2.6; abdominal scutum length 3.2, maximal width 3.6; Femur I 1.9, II 3.1, III 1.9, IV 3.0.

Figures

FIGURE 6. Acumontia succinea sp. nov., habitus of male holotype (USNM): A, dorsal view; B, lateral view. Scale bars = 1 mm.

FIGURE 7. Acumontia succinea sp. nov., male paratype (USNM): A – B, habitus, dorsal and lateral views, respectively; C, posterior view; D, dorsum, oblique view. Scale bars = 1 mm.

FIGURE 8. Acumontia succinea sp. nov., male paratype (USNM): A, right chelicera, ectal view, B, left chelicera frontal view; C, left pedipalp, mesal view; D, right pedipalp, ectal view. Scale bars, A – B = 0.5 mm, C – D = 1 mm.

FIGURE 9. Acumontia succinea sp. nov., male paratype (USNM): A, right coxa I, ventral view; B, habitus, ventral view; C, detail of coxa I in ventral view; D, detail of sternum and genital opercle. Scale bars, A, D = 0.5 mm, B = 1 mm, C = 0.05 mm.

FIGURE 10. Acumontia succinea sp. nov., male paratype (USNM): A – C, right leg I, A, trochanter, femur, patella, tibia, metatarsus, tarsus; B, tarsus in detail; C, ventral notch of calcaneus; D, calcaneus and tarsus of right leg II; E, trochanter, femur, patella, tibia, metatarsus, tarsus of right leg III; F, trochanter, femur, patella, tibia, metatarsus, tarsus of right leg IV. Scale bars, A, D – F = 1 mm, B = 0.5 mm, C = 0.1 mm.

FIGURE 11. Acumontia succinea sp. nov., penis of male paratype (USNM): A, truncus and glans, dorsal view; B – E, distal part, B, dorsal view, C, ventrolateral view, D, apical view, E, ventral view, F, stylus and ventral process, lateral view, G, dorsal process, lateral view. Scale bars, A = 0.2 mm, B – E = 0.1 mm, F – G = 0.05 mm.

FIGURE 12. Northern Madagascar, showing distribution of the Triaenonychini in the WWF Terrestrial Ecoregions (AT = Afrotropical). Circles = Acumontia species; pentagons = minor genera; triangle = Acumontia succinea sp. nov.

Tables

TABLE 1. Appendage measurements of male holotype of Acumontia succinea sp. nov.

	Trochanter	Femur	Patella	Tibia	Metatarsus	Tarsus	Claw
Pedipalp	0.6	2.3	1.3	1.5	-	1.5	0.5
Leg I	0.7	2.6	0.8	1.8	2.3	1.2	-
Leg II	0.7	4.0	1.0	3.6	4.4	3.4	-
Leg III	0.6	2.6	1.0	2.1	3.4	1.6	-
Leg IV	0.7	4.0	1.3	3.1	5.2	2.0	-