Traegaardhia holsingeri ( Zacharda, 1980 ) Zacharda & Fong & Hobbs Iii & Piva & Slay & Taylor, 2010

Zacharda, Miloslav, Fong, Daniel, Hobbs Iii, Horton H., Piva, Erminio, Slay, Michael E. & Taylor, Steven J., 2010, 2474, Zootaxa 2474, pp. 1-64 : 45-50

Traegaardhia holsingeri ( Zacharda, 1980) , new combination ( Figs 32–35)

Rhagidia cavernarum ( Packard, 1888) Holsinger, 1965 , Acarologia 7, 658–661.

Foveacheles (Mediostella) holsingeri Zacharda, 1980 , Acta Universitatis Carolinae, Biologica, (1978), 677–679. Foveacheles cf. holsingeri: Zacharda, 1985 , V ě stník Ċ eskoslovenské spole č nosti zoologické, 49, 78.

Material examined

NEOTYPE: adult male, Arkansas, Searcy Co., In-D-Pendands Cave, coll. M.E. Slay, C. Brickey, G.O. Graeming, D. Fenolio, 12.9.2004, deposited in the Museum of Biological Diversity , Ohio State University, Type No. OSAL0007390; paratypes (deposited with the neotype): adult female, U.S.A., Missouri, Pulaski Co. , Fort Leonard Wood , Wilson Cave , 7.24 km SW of St. Robert, coll. S.J. Taylor, M.E. Slay, 5.1.2004, OSAL0007395; adult female, Arkansas, Newton Co. , Tom Barnes Cave , coll. N. & J. Youngsteadt, 4.3.2005, OSAL0007391; adult female, Oklahoma, Delaware Co., January-Stansbury Cave , coll. D. Fenolio, May 2002, OSAL0007392; adult male, Arkansas, Marion Co. , Square Cave , coll. M.E. Slay, C.J. Bitting, 22.7.2004, OSAL0007393; adult male, Arkansas, Caroll Co. , Sandy Cave , coll. D. Kampwerth, B. Wagner, 18.9.2002, OSAL0007394; Arkansas, Stone Co. , Janus Pit, coll. G.O. Graening, M.E. Slay, D. Kampwerth, E. Cofrey, 1.2.2003.

Diagnosis

Prodorsal filiform bothridial setae sc 1 shorter than sc 2, not overlapping transverse disjugal suture. Dorsal opisthosomal setae c 1, d 1, e 1 short, about one third of distance to insertions of successive setae. Cheliceral fixed digit with lateral fissure located at level of insertion of proximal cheliceral seta and small spiculate thorn at base of digit; movable digit serrated along approximately distal half of masticatory surface. Proximal cheliceral seta inserted at level of articulation of movable digit, its tip does not reach insertion of distal seta. Palpal tarsus same length as femorogenu, with ten pubescent setae. Coxae I, II, III, IV with 3-1-6-4 pubescent setae, respectively. Rhagidial organ I comprised of four extremely long and slender rhagidial solenidia (ω) lying obliquely in separate depressions; stellate famulus (ε) between first and second proximal rhagidial solenidia antiaxially; rhagidial organ II with four rhagidial solenidia lying in tandem in confluent depressions, or solenidia may be slightly oblique and distal solenidion separated from the others; small spiniform famulus (ε) subtending proximal rhagidial solenidion.

Affinities

Traegaardhia holsingeri ( Zacharda, 1980) is similar to T. cavernicola n. sp. from which it differs in the following morphological characteristics. (1) In the rhagidial organ I the stellate famulus is inserted between the first and second rhagidial solenidia; in T. cavernicola it is inserted between the second and third rhagidial solenidia. (2) The rhagidial organ II is comprised of four rhagidial solenidia lying in tandem in confluent depressions; in T. cavernicola the rhagidial organ II is comprised of three separate oblique rhagidial solenidia. (3) The cheliceral fixed digit bears a tiny basal spiculate thorn and the masticatory surface of movable digit is serrate; in T. cavernicola the basal spiculate thorn at basis of cheliceral movable digit is absent and the masticatory surface of movable digit is smooth. (4) The coxae I, II, III, IV are with 3-1-6-4 finely pubescent setae, respectively; in T. cavernicola the coxae I, II, III, IV are with 3-1-5-3 setae, respectively.

Traegaardhia holsingeri also partly resembles T. paralleloseta ( Zacharda, 1985) , (see below), particularly in the morphology of rhagidial organs I and II which are comprised of the very long and slender rhagidial solenidia. However, these two species differ from each other in many diagnostic characters: (1) In T. holsingeri the insertion of distal cheliceral seta is located about in the middle of length of fixed cheliceral digit; in T. paralleloseta it is located distinctly distally. (2) In T. holsingeri the dorsoproximal spiniform solenidia on tibiae I, II and III are erect; in T. paralleloseta all dorsodistal solenidia on tibiae I and II are recumbent, lying in superficial depressions and resembling small rhagidial solenidia. Also the dorsoproximal parallel solenidia on the tibia III are recumbent. (3) In T. holsingeri the rhagidial organ II is comprised of four long rhagidial solenidia in tandem; in T. paralleloseta only three separate oblique rhagidial solenidia are in rhagidial organ II. (4) In T. holsingeri the erect spiniform solenidion on genu III is dorsoproximal; in T. paralleloseta it is dorsodistal.

Redescription

Adult female (three examined). Length of idiosoma 1114(976–1280) µm. Ratio of leg I length to idiosomal length 1.51(1.27–1.83).

Gnathosoma . Subcapitulum moderately slender, subtriangular ( Fig. 33C); ratio of length to breadth 1.25(1.21–1.27); distal hypostomal lips with spiniform internal and serrate external malar processes; adoral setae nude; proximal subcapitular setae pubescent, external pair longer than internal pair. Dorsal surface of chelicera with shallow saddle-shaped depression at level of bases of digits ( Fig. 33A,B); cheliceral digits elongated and attenuated; dorsal surface of fixed digit with short narrow rim at level of basis of distal cheliceral seta; fixed digit terminates in two cusps, smooth along masticatory surface and with distinct lateral fissure located at level of insertion of proximal cheliceral seta; movable digit serrated along approximately distal half of masticatory surface. Small spiculate thorn at basis of fixed digit ( Fig. 33B). Chelicera with two setae; proximal seta inserted above articulation of movable digit; tip of proximal seta does not reach insertion of distal seta; tip of distal seta slightly overlaps apex of fixed digit. Length of chelicera 257(247–264) µm, dorsoventral width 86(82–92) µm, length of movable digit 82(79–89) µm, length of proximal and distal cheliceral setae 22(16–26) and 56(43–66) µm, respectively, distance between their insertions 26(23–30) µm. Ratios: cheliceral length to dorsoventral width 3.01(2.67–3.20), length of movable digit to length of chelicera 0.32(0.30– 0.33), length of movable digit to dorsoventral width of chelicera 0.96(0.86–1.08). Palpal tarsus about same length as femorogenu ( Fig. 33D); ratio of length to width of tarsus 3.60(3.0–4.40). Length of palpal trochanter, femorogenu, tibia and tarsus 45(43–46), 135(122–142), 71(69–73) and 132(122–145) µm, 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 ( Fig. 32A). Seatae v 2 very short, shorter than distance between insertions of v 2 –sc 2. Bothridial setae sc 1 filiform, finely pubescent, not overlapping transverse disjugal suture. Setae sc 2 longer than sc 1. Length of setae: v 1 85(73–99), v 2 58(56–63), sc 1 148, sc 2 165 µm.

Opisthosomal dorsum and anal region. Cupules ia positioned laterally about midway between insertions of setae c 1 and d 1; im lateral and just anterior to setae e 1; ip slightly distad of setae f 2; ih positioned ventrolaterally between insertions of adanal ad 1 and posteriormost aggenital setae ( Fig. 32A,B). Setae c 1, d 1, e 1 reach about one third of distance to insertion of successive seta; seta f 1 reaches one half of distance to insertion of h 1. Length of setae: c 1 58(53–63), c 2 140(135–145), d 1 59(53–63), e 1 57 (49–63), f 1 77(66–82), f 2 56(53–59), h 1 133(125–138), h 2 74(66–79), ps 1 110(105–115), ps 2 63(49–66), ps 3 50(36–59), ad 1 56(52–68) µm.

Podosoma. Coxae I, II, III, IV symmetrically with 3-1-6-4 finely pubescent setae, respectively.

Genital region. Genital valves symmetrically each with five or six finely pubescent genital setae (g) of similar length, about 46(43–49) µm, arranged evenly along medial edge of valve; sometimes 6 and 4 setae on each valve asymmetrically ( Fig. 32B). Five pairs of aggenital setae (ag) of similar length, about 57(53–69) µm. Length of genital valves 149(148–152) µm.

Legs. Leg I 1664 (1568–1792) µm long, about 1.51(1.27–1.83) as long as idiosoma. Empodia of all legs setulose, slender, slightly longer than claws; claws each with small clawlet ventrobasally. Number of setae and solenidia (solenidia and famulus (ε) bracketed), respectively, on legs I-II-III-IV ( Figs 34, 35): trochanters 1-1- 2-2, basifemora + telofemora 5+5-6+5-4+4-3+4, genua 12(1)-9(1)-7(1)-6, tibiae 11(2)-8(2)-7(2)-6(1), tarsi 19(4+ε)-16(4+ε)-14-14. Genua I and II each with one erect spiniform distoventral solenidion (σ); genu III with one small spiniform dorsoproximal solenidion. Tibia I with one erect spiniform dorsoproximal solenidion (Φ) and one small dorsodistal rhagidial solenidion ( Fig. 34C); tibia II with one spiniform erect dorsoproximal solenidion, and one large lanceolate dorsodistal solenidion recessed in deep pit with broadly open surface pore ( Fig. 34D); tibia III with two erect dorsoproximal spiniform solenidia arranged in tandem ( Fig. 35A); tibia IV with one erect spiniform dorsoproximal solenidion. Tarsus I slender, its tip slightly tapers in lateral view, ratio length to width 6.82(6.12–7.69), with four extremely long and slender rhagidial solenidia (ω) lying obliquely in separate depressions; stellate famulus (ε) between first and second proximal rhagidial solenidia antiaxially ( Fig. 33E). Tarsus II with four rhagidial solenidia lying in tandem in confluent depressions ( Fig. 33F), sometimes solenidia may be slightly oblique and distal solenidion is separate ( Fig. 33G); small spiniform famulus (ε) subtending proximal rhagidial solenidion .

Adult male (three examined). Typical club-shaped sperm sac showing through the tegument of opisthosoma, otherwise as in females.

Remarks

Traegaardhia holsingeri was originally collected by T. C. Barr in the Mammoth Cave, Edmonson Co., Kentucky, and erroneously determined as Rhagidia cavernarum ( Packard, 1888) by Holsinger (1965). Subsequently Zacharda (1980) recognized that Packard (1888) used two different names, i.e., Rhyncholophus cavernarum and Bryobia (Penthaleus) weyerenensis for the same species of rhagidiid mite. Zacharda (1980) identified this mite as a representative of the genus Poecilophysis Cambridge, 1876 . Thus Rhyncholophus cavernarum Packard, 1888 = Bryobia (Penthaleus) weyerenensis Packard, 1888 = Rhagidia cavernarum ( Packard, 1888) sensu Holsinger (1965) are the synonyms of the valid name Poecilophysis weyerenensis ( Packard, 1888) . Therefore the specimens which were collected by T. C. Barr in the Mammoth Cave and determined by Holsinger as Rhagidia cavernarum had to be renamed. These were named holsingeri after the speleobiologist Professor John R. Holsinger, Old Dominion University, Norfolk, Virginia, and placed into the genus Foveacheles Zacharda, 1980 . The type specimens of F. holsingeri ( Zacharda 1980: 679.) as well as a specimen from the Dry Cave, Hardin Co., Kentucky ( Zacharda 1985: 78.) were distorted in the examined micropreparations and thus did not allow good illustrations of the diagnostic morphological characters in this species. Because the types are probably lost (Holsinger, pers. comm.), a neotype for Traegaardhia holsingeri ( Zacharda, 1980) was designated, which is now deposited in the Museum of Biological Diversity, Ohio State University, Columbus.

The diagnosis, redescription and drawings of T. holsingeri are based on the morphology of the undistorted and undamaged specimens which are recognized to be representatives of the genus Traegaardhia . However, designating a neotype from the Ozarks (Arkansas, Missouri) ( Fig. 1B) for a species originally described from the Interior Low Plateaus of Kentucky ( Fig. 1B), a different karst region, might eventually prove problematic. In the future, it is possible that a detailed molecular analysis of the populations from Kentucky (Mammoth Cave) and the Ozarks could find significant genetic divergence, potentially identifying these as two unique species. Thus, although it would be desirable to designate a neotype based on material from Mammoth Cave, there are no suitable specimens for such a designation.

Troglomorphisms such as the strikingly elongated and attenuated rhagidial solenidia in the rhagidial organs I and II indicate T. holsingeri is a troglobiont.