Volume 11, pp , September 30, 1972

Transcription

1 A NEW CAVERNICOLOUS HARVESTMAN FROM WESTERN AUSTRALIA (ARACHNIDA: OPILIONES: TRIAENONYCHIDAE) By G. S. HUNT Reprinted from the Journal of the Australian Entomological Society, Volume 11, pp , September 30, 1972

2 232 A NEW CAVERNICOLOUS HARVESTMAN FROM WESTERN AUSTRALIA (ARACHNIDA : OPILIONES : TRIAENONYCHIDAE) BY G. S. HUNT* [Manuscript received March 3, 1972] Abstract A new cavernicolous harvestman, Calliuncus labyrinthus sp. n., is described from the Margaret River limestone caves, Western Australia. The genus Calliuncus Roewer is redefined and a key given for males of its six species. The new species possesses the cave adaptations of light colour and relatively long thin legs, unlike other harvestmen recorded in Western Australian caves. INTRODUCTION Few species of harvestmen have been recorded in Western Australian caves. "Spinicrus sp." (Phalangiidae, Megalopsalinae) has been taken from the dark zone, entrance zone and doline of several caves on the Nullarbor Plain and has been collected on the surface at night. It is regarded as a troglophile (Richards 1971). Other harvestmen records are from the Augusta-Margaret River dune limestone area. Spinicrus minimus Kauri has been collected in Mammoth Cave (Kauri 1955), but also occurs on the surface. The harvestmen noted by Hamilton-Smith (1965) were probably megalopsalines or the triaenonychid Nunciella aspera (Pocock). Both are common just inside cave entrances and on the surface and are probably best regarded as trogloxenes, rather than "first level troglophiles" as suggested by Hamilton-Smith (1967). Numerous specimens of N. aspera have been collected under wood and rock debris in Strongs Cave doline (Hunt 1971). Calliuncus labyrinthus sp. n., also from the Margaret River caves, possesses modifications generally regarded as cave adaptive and has not been collected from surface habitats. Only two cave adapted Australian harvestmen have been previously described : Holonuncia cavernicola Forster from Jenolan Caves, New South Wales (Forster 1955) and Monoxyomma cavaticum Hickman from Hastings and Ida Bay Caves (Hickman 1958; Goede 1967). They are usually found in the dark zone. Cavernicolous adaptations in these and some undescribed harvestmen are discussed elsewhere (Hunt, in press). Family TRIAENONYCHIDAE Soerensen 1886 Subfamily TRIAENONYCHINAE Pocock 1903 Tribe TRIAENONYCHINI Pocock 1903 Genus Calliuncus Roewer 1931 Calliuncus Roewer, 1931: 166; Hickman, 1958: 51. Type species, by original designation: Calliuncus ferrugineus Roewer. Species previously placed in the genus are C. ferrugineus Roewer and C. glaber Kauri (both Western Australia), C. ephippiatus Roewer (Victoria), and C. odoratus Hickman and C. vulsus Hickman from Tasmania (Roewer 1931; Kauri 1955; Hickman 1958; 1959). Amendments and additions to earlier diagnoses of the genus are necessary. Generic diagnosis Eyemound rising from or just behind unarmed anterior margin of carapace, rounded apically except for small anterior slightly curved spine. Scute and free tergites without spines and tubercles although tergal areas and free tergites sometimes with rows of large granules. Tergal areas 4 and 5 usually separated by groove. Male chelicera typically with proximal retrodorsal boss, male pedipalp with strongly bifid proximoventral tooth. Each calcaneus much shorter than astragalus, that of metatarsus 1 without ventral notch. Tarsal formula: 3(2), 6-9(3-4), 4, 4 (distitarsi in parentheses). Penis with small tongue-shaped process between lateral plate and aedeagus proper. Glans enclosed to varying degrees by flanking, generally wing-like plates. Each ventral plate with strong superior seta and three inferior setae. *School of Zoology, University of New South Wales, Sydney, 2033.

3 A NEW CAVERNICOLOUS HARVESTMAN 233 FIGS Calliuncus labyrinthus sp. n.: (1) dorsum of male, lateral view; (2) coxo-sternal region of male, left side; (3) second segment of chelicera of male, dorsal; (4) pedipalp of male, prolateral; (5) pedipalp femur of female, prolateral; (6) femur of leg 1, retrolateral; (7) metatarsus and tarsus of leg 1, retrolateral. Each scale bar indicates 0.5 mm; Figs 1, 4 and 5 at same scale.

4 234 G. S. HUNT The six species now placed in Calliuncus may be separated by the following key. Females are not known for all species, so the key is based on male characters (except for C. ephippiatus?). KEY TO MALES OF SPECIES IN GENUS Calliuncus ROEWER 1. Prolateral surface of pedipalp femur with no subdistal teeth or tubercles C. ferrugineus Roewer Prolateral surface with at least one subdistal tooth or tubercle Pedipalp femur with 4 conspicuous dorsal teeth.. 3 Pedipalp femur with 3 conspicuous dorsal teeth Body length greater than 4.0 mm and subdistal prolateral teeth on pedipalp femur small C. glaber Kauri Body length less than 4.0 mm and the subdistal teeth large.. C. ephippiatus Roewer 4. Scute coarsely granular and tergal area 5 with row of larger granules......c. labyrinthus sp. n. Scute very finely granular or without granules, tergal area 5 without row of granules Femur of leg 2 with two distal retroventral teeth..c. vulsus Hickman Femur of leg 2 without such teeth.. C. odoratus Hickman Calliuncus labyrinthus sp. n. Types. Holotype : Strongs Cave, Margaret River area, WESTERN AUS- TRALIA (type locality), under rock in entrance doline, 5.i.1965 (G. S. Hunt), Australian Museum (A.M.), Sydney, K Allotype : Labyrinth Cave, Margaret River area, dark zone of cave (Wombat Warren section), 25.i.1969 (J. W. J. Lowry), A.M., K Paratype (slightly damaged): Labyrinth Cave (Wombat Warren section), 9.viii.1969 (J. W. J. Lowry), A.M., K Holotype male Measurements (mm).-length scute 2.34, width scute 1.99, length carapace 1.24, length genital operculum 0.35, width genital operculum Cox. Troch. Fem. Pat. Tib. Met. Tar. Total Leg Leg Leg Leg Pedipalp Chelicera : first segment 0.89, second segment 1.03, total 1.92 Colour.-Body uniform yellow but with traces of dark brown pattern, including reticulations on carapace and indications of median stripe posterior to scutal groove. Chelicerae orange-yellow, other appendages yellow. Body (Figs. 1, 2).-Eyemound of low profile, about half as high as long, rising steeply from just behind anterior margin of carapace but sloping back gently posterior to small anterior spine. Process on anterior margin abutting cheliceral boss large. Scute and free tergites coarsely granular. Each tergal area and free tergite with enlarged mesial granules tending to form row. Carapace over half length of scute. Groove between areas 4 and 5 faintly indicated. Genital operculum with scattered hairs, sternites with rows of hairs. Spiracle slightly obscured by bridging granules. Penis (Figs. 8-10).-Apical portion complex. When penis not expanded small section of glans exposed dorsally (Figs. 9, 10), more distally glans curved ventrad between two large flanking wing-like plates. Apical portion of glans curved dorsad, equipped dorsolaterally with pair of large curved spinous processes. Lateral tongue-shaped process partly obscured by ventral plate, not rugose. Viewed laterally (Fig. 9), ventral plates deeply concave with inferior setae inserted well inside concavity. Ventral plates partly separated by thin mediodistal fissure (Fig. 8). Chelicerae (Fig. 3).--First segment constricted proximally, boss small, distal prodorsal spine small. Dorsum of second segment with two large tubercles and several small granules as in Fig. 3.

5 A NEW CAVERNICOLOUS HARVESTMAN 235 FIGS Penis, Calliuncus labyrinthus sp. n.: (8) ventral; (9) lateral; (10) dorsal. Scale bar indicates 0.1 mm. Pedipalps (Fig. 4, venter coxa Fig. 2).-Femur with 4 ventral teeth : tooth 1 (most proximal) strong and bifid, 3 weakest, 4 strongest and slightly curved. Dorsally, small denticle and three teeth in proximal half. Prolateral surface with small submesial tubercle in distal third, retrolateral surface essentially smooth. Prolateral surface of patella with small granule only. Retroventral margin of tibia with blunt denticle and three teeth, proventral margin with small denticles in proximal and two teeth in distal half. Margins of tarsus with 4 and 3 teeth respectively. Legs (Figs. 2, 6, 7).-Long and thin. Venter of coxae as in Fig. 2: coxa 1 with large flattened prodistal tooth opposing bifid proximoventral tooth of pedipalp femur, strong conical tooth more proximally; venter coxa 4 without mesial granules. Venter of femur 1 with row of small tubercles and granules (Fig. 6). Metatarsus as in generic description (Fig. 7). Tarsal formula: 3(2), 8-9(3-4), 4, 4. Allotype female Measurements (mm).-length scute 2.12, width scute 1.92, length carapace 1.14, length genital operculum 0.39, width genital operculum Cox. Troch. Fem. Pat. Tib. Met. Tar. Total Leg Leg Leg Leg Pedipalp Chelicera: first segment 0.74, second segment 0.89, total Female characteristics.-resembles male but differs in following: colour pattern without median stripe; body smaller, genital operculum larger, chelicerae and pedipalps smaller; proximal boss on cheliceral first segment absent and, correlated with this, process on anterior margin much reduced; proximoventral tooth on pedipalp femur more slender, not as markedly bifid (Fig. 5), followed distally by two teeth (equivalent to teeth 2 and 4 of male, tooth 4 less strong than in male) ; prodistal tooth on coxa 1 venter more conical, not as strong and blade-like; tarsal formula: 3(2), 8-9(4), 4, 4. Variations The collection comprises only the three type specimens. The paratype male is of interest as the usual secondary sexual characteristics are not well developed : cheliceral boss barely discernible; proximoventral tooth on pedipalp femur only weakly bifid and, as in the female, followed by two teeth compared with three in holotype (a small denticle occupies a similar position to tooth 3 on the right pedipalp femur of paratype); ventral prodistal tooth on coxa 1 not blade-like; body smaller than both holotype and female (scute length 2.06 mm, scute width 1.81, carapace length 1.11).

6 236 G. S. HUNT The variation between holotype and paratype males suggests male dimorphism, common in some New Zealand and Australian triaenonychids (Forster 1954; Hunt 1971). A larger series from different caves needs to be examined, however, before the significance of this variation can be determined. Comments The overall structure of the male genitalia is similar to that of other species in the genus for which descriptions have been given, but also strongly resembles that in Nunciella aspera (Pocock), the type species of genus Nunciella Roewer. This similarity supports the belief (Hunt 1971) that the genera are closely related. The Nunciella penis, however, does not possess the lateral tongue-like process. Calliuncus labyrinthus sp. n. can be readily separated from other species in the genus by its small light-coloured coarsely granular body, its relatively long legs and by the structure of the male genitalia. The light colouration and long legs may be regarded as cave adaptations, in common with other cave triaenonychids (Hunt, in press). The tendency for four segments in distitarsus 2 (three in other species) may indicate a trend towards increase in tarsal segmentation noted by Forster (1965) in New Zealand cave species. More material is needed to establish this. One should hesitate in applying the terms "troglophile" or "troglobite" to this species until its biology is known and the surface fauna adequately sampled. ACKNOWLEDGMENTS I wish to thank Mrs. J. W. J. Lowry, School of Zoology, University of New South Wales, who is currently studying the ecology of Western Australian caves, for making available her collection of cave harvestmen. I should also like to thank Dr. A. M. Richards, School of Zoology, University of New South Wales, and Mr. M. Gray, Arachnologist at the Australian Museum, Sydney, for criticisms of the manuscript. REFERENCES FORSTER, R. R. (1954).-The New Zealand harvestmen (sub-order Laniatores). Canterbury Mus. Bull. 2; FORSTER, R. R. (19551 Further Australian Opiliones. Aust. J. Zool. 3: FORSTER, R. R. (1965).-Harvestmen of the suborder Laniatores from New Zealand caves. Rec. Otago Mus. 2: GOEDE, A. (1967).-Tasmanian cave fauna: character and distribution. Helictite 5: HAMILTON-SMITH, E. (1965). Some preliminary notes on the Western Australian cave fauna. The Western Caver 5: 1-5. HAMILTON-SMITH, E. (1967).-The Arthropoda of Australian caves. J. Aust. ent. Soc. 6: HICKMAN, V. V. (1958). Some Tasmanian harvestmen of the family Triaenonychidae. Pap. Proc. R. Soc. Tasm. 91: HICKMAN, V. V. (1959). Calliuncus vulsus nom. nov. (Opiliones). Pap. Proc. R. Soc. Tasm. 93: vi. HUNT, G. S. (1971).-The genus Nunciella Roewer (Opiliones, Laniatores) with description of a new species from Kangaroo Island, South Australia. Proc. Linn. Soc. N.S. W. 96: HUNT, G. S. (1972).-Notes on Australian cave harvestmen. 8th bienn. Conf Aust. speleol. Fed. Proc.,Dec. 1970: KAURI, H. (1955).-Report from Professor J. Gislén ' s expedition to Australia in Harvest-spiders from S.W. Australia. Acta Univ. Lund. N.F., Avd. 2, 50: RICHARDS, A. M. (1971). An ecological study of the cavernicolous fauna of the Nullarbor Plain, southern Australia. J. Zool. (Lond.) 164: ROEWER, C. Fr. (1931).-Ober Triaenonychidae (VI Ergänzung der "Weberknechte der Erde ", 1923). Zeits. wiss. Zool. 138: