Foveacheles gigantea, Zacharda, 2000

Zacharda, Miloslav, 2000, New species of the rhagidiid genus Foveacheles (Acari: Prostigmata: Eupodoidea) with a lyri ® ssure-like structure on the chelicerae, Journal of Natural History 34 (2), pp. 247-265 : 248-253

Foveacheles gigantea n. sp.

(®gures 1±3)

Material examined

All from Czech Republic. HOLOTYPE: adult female, deposited in the Canadian National Collection of Insects and Arachnids, Ottawa, in micropreparations, Type No. 22,403; North Bohemia, C Ï eske  StrÏedohorÏõ Mts, PruÊ cÏelska  rokle-gorge near Brna  -village, S of town of U  stõ nad Labem (14ss05 ¾E,50ss08 ¾N), collected in pitfall traps positioned in subterranean spaces of a basalt talus slope, about 330±400 m altitude, left in place from 5 April 1991 to 3 May 1992. PARATYPES: one adult female and two males, collected in pitfall traps 20 February 1991 to 22 March 1992, otherwise same data as holotype; all collected by V. RuÊzÏicÏka .

D iagnosis

Chelicerae with elongated and attenuated digits and with lyri®ssure-like structure on ®xed digit positioned antero-laterally and slightly distad of articulation of movable digit. Dorsal surface of ®xed digit with indistinct narrow rim. Proximal cheliceral seta inserted distinctly distad of articulation of movable digit.Tip of proximal cheliceral seta almost reaching insertion of distal seta. Rhagidial organ II consists of three rhagidial solenidia lying in tandem in separate depressions, and spiniform famulus, e, subtending proximal rhagidial solenidion. Bothridial setae sc 1 long, overlapping disjugal suture. Spiniform solenidia on genua I, II and III medioventral and lateroventral, proximal, respectively. Solenidion on tibia IV proximal, laterodorsal.

D escription

Adult female (two examined). Length of idiosoma 1488±1584 m m. Ratio of leg I length to idiosomal length 1.08±1.32.

Gnathosoma . Subcapitulum slender, subtriangular (®gure 2G); ratio of length to breadth 1.39±1.47; distal hypostomal lips with spiniform internal malar and serrate external malar processes; adoral setae nude; proximal subcapitular setae ciliate, external pair slightly longer than internal pair. Dorsal surface of chelicera with distinct saddle-shaped depression at level of bases of digits (®gure 2A); cheliceral digits long, robust; dorsal surface of ®xed digit with indistinct narrow rim; ®xed digit terminates in three cusps, smooth along masticatory surface and with distinct lateral oblique lyri®ssure-like structure positioned above and slightly distad of articulation of movable digit; movable digit serrated along approximately distal half of masticatory surface. Chelicerae with two setae inserted distad of articulation of movable digit; tip of proximal seta just reaching (or almost reaching) insertion of distal seta; tip of distal seta overlaps apex of ®xed digit. Length of chelicera 353± 402 m m, dorsoventra l width 148±188 m m, length of movable digit 135±148 m m, length of proximal and distal cheliceral setae 39±43 and 56±59 m m, respectively, distance between their insertions 43±46 m m. Ratios: cheliceral length to dorsoventral width 2.13±2.38; length of movable digit to length of chelicera 0.37±0.38; length of movable digit to dorsoventral width of chelicera 0.79±0.91. Palpus robust (®gure 2H), with relatively slender tarsus; ratio of length to width of tarsus 2.86±3.18. Length of palpal trochanter, femorogenu, tibia and tarsus 49, 181±214, 63±72 and 142±186 m m, respectively. Number of setae and solenidia (in brackets) on palpal trochanter, femorogenu, tibia and tarsus 0-2-3-10(1), respectively; tarsal solenidion spiniform, erect.

Prodorsum. Naso well-developed, with pair of internal vertical setae v 1. Bothridial setae sc 1 ®liform, ®nely pubescent, overlapping disjugal suture (®gure 1A). Length of setae: v 1 99, v 2 92±96, sc 1 158±162, sc 2 185±204 m m. Eyes not visible.

Opisthosomal dorsum. Complement and arrangement of dorsal setae and cupules typical for Rhagidiidae (®gure 1A); three pairs of cupules; ia positioned laterally about midway between setae c 1 and d 1, im lateral and just anterior to setae e 1, ip laterally between setae e 1 and f 1, distad of insertion of f 2. Setae c 1, d 1, e 1, f 1 reach 0.53, 0.48, 0.40, 0.96 of distance to insertion of successive seta. Length of setae: c 1 92±102, c 2 204±208, d 1 82±92, e 1 82±89, f 1 165±175, f 2 99±112, h 1 188±231, h 2 115± 122 m m.

Podosoma. Coxisternal plates (epimeres) I, II, III, IV with 3-1-5-3 or 3-1-6-3 ®nely pubescent setae, respectively (®gure 1B). (One specimen with ®ve and six setae on coxisternal plates III.)

Genital region. Genital valves each with ®ve ®nely pubescent setae of similar length, 43±66 m m, arranged evenly along medial edge of valve. Five pairs of aggenital (paragenita l) setae of similar length, 66±72 m m (®gure 1B). Length of genital valves 204± 214 m m. Cupules ih positioned ventrolaterally, proximad of posteriormost pair of aggenital setae.

L egs. Leg I 1712 ±1968 m m long, 1.08±1.32 times idiosomal length. Empodia of all legs setulose, broadly oval in dorsoventral view, slightly longer than claws; claws each with small clawlet ventrobasally. Number of setae and solenidia (solenidia and famulus, e, bracketed), respectively, on legs I-II-III-IV: trochanters 1-1-2-2; basif emora +telofemora 5 +5-6 +5-4 +4-3 +4; genua 11(1)-9(1)-7 (1)-6; tibiae 11 (2)-7 (2)-7(2)-7 (1); tarsi 19(4 + e)-16 (3 + e)-14-14 (®gure 3). Genua I and II each with one erect spiniform medioventral solenidion, genu III with one lateroventral proximal small spiniform solenidion. Tibia I with one dorsoproximal erect spiniform solenidion, and one dorsodistal rhagidial solenidion recessed in longitudinal depression (®gure 2E); tibia II with one laterodorsal, proximal spiniform erect solenidion, and one lanceolate dorsodistal solenidion recessed in deep pit with broadly open surface pore (®gure 2F); tibia III with two erect spiniform laterodorsal proximal solenidia arranged in tandem; tibia IV with one erect spiniform laterodorsal proximal solenidion. Tarsus I slender, its tip slightly truncated in lateral view, ratio length to width 5.27±6.64, with four (exceptionally three) rhagidial solenidia lying obliquely in separate depressions, stellate famulus, e, inserted between ®rst and second proximal rhagidial solenidia antaxially (®gure 2B) or subtending proximal rhagidial solenidion (®gure 2C); tarsus II with three rhagidial solenidia lying in separate depressions arranged in tandem and small spiniform famulus, e, subtending proximal rhagidial solenidion (®gure 2D).

Adult male (four examined)

Because sexual dimorphism in the family Rhagidiidae is only marked in the internal genitalia ( Baker, 1990), a full description of male features is not given. Measurements of male morphological characters are as follow: length of idiosoma 1168± 1504 m m, ratio of leg I length to idiosomal length 1.22±1.42.

Length of chelicera 326±353 m m, dorsoventra l width 135±148 m m, length of movable digit 122±135 m m, length of proximal and distal cheliceral setae 36±43 and 53± 56 m m, respectively, distance between their insertions 40±43 m m. Ratios: cheliceral length to dorsoventral width 2.31±2.52; length of movable digit to length of chelicera 0.37±0.38; length of movable digit to dorsoventral width of chelicera 0.89±0.98; length to width of palpal tarsus 2.66±3.20. Length of palpal trochanter, femorogenu, tibia and tarsus 46±56, 175±181, 53±59 and 132±158 m m, respectively. Length of prodorsal setae: v 1 79±82, v 2 82±105, sc 1 135±162, sc 2 182± 204 m m; length of opisthosomal setae: c 1 96±112, c 2 204±224, d 1 82±102, e 1 92±102, f 1 165±188, f 2 115±122, h 1 198± 231, h 2 122± 138 m m.

Podosom a. Coxisternal plates (epimeres) I, II, III, IV with 3-1-5-3 ®nely pubescent setae, respectively.

Genital region. Genital valves each with ®ve ®nely pubescent setae of similar length, about 43±59 m m. Five pairs of aggenital (paragenital) setae of similar length, about 66±82 m m. Sperm sac showing through the integument longitudinally oval, club-shaped.

L egs. Leg I 1664 ±1952 m m long, about 1.22±1.42 as long as idiosoma. Ratio of tarsus I length to dorsoventral width 6.12±6.56. Setal complement and arrangement as in female.

A nities

Adults of Foveacheles gigantea n. sp. di er from those of the similar F. proxima n. sp. by the following: the tip of the proximal cheliceral seta almost reaches the insertion of the distal seta, whilst in F. proxima it is distinctly short of it; rhagidial organ II consists of three solenidia lying in tandem in separate depressions and the spiniform famulus subtends the proximal rhagidial solenidion, whilst in F. proxima the solenidia in rhagidial organ II are oblique and the famulus is lateral to the proximal rhagidial solenidion; bothridial setae sc 1 are long and overlapping the disjugal suture, whilst in F. proxima they only reach or slightly overlap the disjugal suture; the spiniform solenidion on tibia IV is proximal and laterodorsal, whilst in F. proxima this solenidion is medial and lateroventral. Eyes large, conspicuous in F. proxima , not evident in F. gigantea .

Foveacheles gigantea n. sp. di ers from F. halltalensis n. sp. by the following: the solenidia in rhagidial organ II are in separate depressions, whilst in F. halltalensis they are in conūent depressions; the bothridial setae sc 1 are long and distinctly overlap the disjugal suture, whilst in F. halltalensis they are strikingly shorter, not overlapping the disjugal suture; the spiniform solenidia on genua I, II and III are positioned ventrally, whilst in F. halltalensis they are positioned dorsally.

Foveacheles gigantea n. sp. is also similar to the troglobitic F.(Spelaeocheles) troglodyta which di ers from F. gigantea by the following: the rhagidial organs I and II consist of ®ve and four separate oblique rhagidial solenidia, respectively, whilst in F. gigantea four and three rhagidial solenidia are present; the spiniform solenidia on genua I and II are each ventrodistal, whilst in F. gigantea they are positioned ventromedially.

Etymology

The name gigantea indicates the large and robust idiosoma of this newly discovered species.