Ulyxes euryclea, Shaw, 2014

Shaw, Matthew D., 2014, Ulyxes, a new Australopapuan mite genus associated with arboreal nests (Acari: Laelapidae), Zootaxa 3878 (3), pp. 261-290 : 269-275

Ulyxes euryclea sp. nov.

( Figs 10–31 , 56 )

Specimens examined. 1 holotype female, 1 paratype male, 3 paratype females, 9 females, Candlebark Park, Templestowe , Victoria, 37°31’56”S, 145°06’39”E, 15 Nov 1998, I. Temby coll., ex nestbox recently occupied by Cacatua longirostris Long-billed Corella, collected four days after last chick fledged, nest 87 ; 4 females, Stokes Bay, Kangaroo Is , South Australia, 35°37’S 137°12’E, 1 Jun 1999, L. Pedler coll., ex tree hollow occupied by Calyptorhynchus lathamihalmaturinus Glossy Black Cockatoo , “Tragic”, ca. 10 week old nestling present, nest 245 ; 1 female, Cygnet River, Kangaroo Is , South Australia, 35°42’S 137°12’E, 20 Mar 1999, L. Pedler coll., ex tree hollow occupied by incubating female Calyptorhynchus lathami halmaturinus Glossy Black Cockatoo , “Sunglasses”, nest 239 ; 2 females, 1 male, Yellingbo , Victoria, 37º49’S 145º30’ E, 13 May 2002, D. Harley coll., nestbox occupied by Gymnobelideus leadbeateri Leadbeater’s Possum, L 9, nest 486. Holotype and paratypes in QM .

Description of females (n=8). Dorsum. 775 (710–785) long x 545 (500–550) wide, margins and posterior of shield faintly reticulate, becoming smooth anteromedially. Standard 39 setae plus 5–7 medial accessory Jx setae, posterior level J3 ( Fig. 10 ). At least 2 of these accessory setae are placed almost symmetrically. Mediodorsal setae of relatively uniform length, j1 43–54, j2 43–60, z1 25–32, z3 46–68, J2 40–50. J5 30–35, Z5 35–47. Marginal setae slightly longer r2 48–60, r3 52–56, r4 54–62, r5 58–59, S1 55 –63, S2 57 –68, S3 57 –67, S4 55 –65, S5 47 –58. Dorsal shield covers entire dorsum. Z5 smooth. Distinct gland pore posterolaterad px2, within subcircular lacuna 11–13 in diameter.

Gnathosoma . Epistome with essentially smooth edge, some specimens with sparse denticles ( Fig. 11 ). Hypostomal setae h1 41 (33–47), h2 28 (19–29), h3 70 (59–71), capitular seta 45 (46–49). Deutosternal groove parallel-sided, bearing six deutosternal rows with 8–13 denticles per row. Fringed internal malae aligned medially, with short lateral lobes. Tips of fimbriae have distinct swellings ( Fig. 14 ). Corniculi 22 (20–22) long, and somewhat broad. Palp trochanter-tibia holotrichous (2:5:6:14). Palp genu al1 shorter than al2, both distally compressed. Four teeth on fixed digit, with one small tooth distal of uninflated pilus dentilis and three welldeveloped teeth proximal. Tip of fixed digit divided ( Figs 12 , 21 ). Cheliceral seta dorsal, 8 long. Movable digit 63 (59–63) with two well-developed teeth borne on antiaxial edge ( Fig. 16 ). Second cheliceral segment 151–174, first segment 65–71. Labrum projects strongly to level of distal edge of palp femur.

Venter ( Fig. 15 ). Smooth tritosternal base, 35 (35–40) between origin and suture, 17–18 wide at origin, 10–11 at suture. Lacinae are fused 18 (9–18) above level of suture and free for 93 (85–105) ( Fig. 13 ). Sternal shield wider 132 (130–136) than long 116 (114–125). Anterior edge of sternal shield is distinctly recessed or stepped-down immediately internal of st1. Long thin cornua abruptly meet, but do not fuse, with exopodal I. Usual two lyrifissures on sternal shield, with st1 external of first lyrifissure, third lyrifissure is free. St1 62 (60–63), St2 63 (63–72), St3 64 (60–64). Sternal shield extending to level mid-coxa III, concave posteriorly. Genito-ventral shield ( Fig. 15 , 19 ) with 7–8 serially-regular, broadly transverse striae, 204 (190–225) long x 150 (132–150) wide at st5. Maximum width 214 (193–215) at Jv1. Lateral edges of genito-ventral shield subparallel. Longitudinal striae extend to just past Zv1. Genito-ventral shield bearing only st5, associated lyrifissure (iv5) is off shield in soft cuticle. In ovigerous females, the anterior pole of the large egg (405–439 x 305–365), has a distinctive sclerotised plate, maximum width ca. 56 ( Fig. 20 ; see Remarks). Peritreme extends past middle of coxa 1. Principal or external metapodal platelet oval, 43 (39–48) x 15 (14–17). Inner metapodal small oval, 10–22 x 6–10. 22 pairs of setae on unarmed opisthogaster excluding Jv1–3 and Zv1–2. Post-stigmatal plate narrow but retains narrow external rebordering, and usual three pore-like structures, median and posterior pores are connected by short gutter ( Fig. 17 ). Mild exopodal IV lobe, 18–20 wide. Genito-ventral shield reaches to within 0–8 µm of anal plate. Anal plate 97 (95–118) long x 115 (98–115) wide between cribral pores. Maximum width 120 (113–123), cribrum of only two rows in most specimens, portion of third cribral row sometimes present. Para-anal setae 31 (28–36), postanal 46 (38–46).

Legs. Leg setation holotrichous as defined by Evans (1963), genu IV with a single pl seta, proximally positioned. Apically bifid setae distributed between femora I–IV and trochanter IV as femur I ad1, pd2, ad3, femur II ad1, pd2, femur III ad1, trochanter IV pl and femur IV ad1, ad2 ( Fig. 18 ). Ventral setae of tibiae and tarsi II–IV and genu III–IV are stouter than dorsal leg setae. Pretarsal opercula with ca. 7–9 tines. Leg segment lengths as in Table 4 .

Description of males (n=2). As for female except as described below.

Dorsum. Dorsal shield 640–650 x 410–425.

Gnathosoma . Fixed digit with rounded tooth level with pilus dentilis; second small tooth distal. Movable digit, 45–49, not reduced, with usual single tooth and notched apex. Spermatodactyl free in distal half, broad bore, 4 wide at apex with a sharp triangular projection ( Fig. 24 ). Lateral lobes of internal malae have fimbrae with tips expanded. Second cheliceral segment 137–138. Slender corniculi 23–24 long. Hypostomal setae h1 35–41, h2 17–26, h3 35–37, capitular seta 49.

Venter. Tritosternal base 25–30 long to suture, 10 from suture to fork of lacinae. Lacinae 83–88 long. Male genital opening oval 27–30 wide x 17 deep. Opening set anteriorly with posterior edge of opening level with st1 ( Fig. 26 ). Holoventral shield ( Figs 22 , 25 ) bearing st1–5, circumanal setae and 4 other pairs of setae with Jv3 off shield, 112–115 wide at st2, st1 39–45, st2 48–46, st3 47–51. Metapodal platelets subsumed by holoventral plate. Holoventral shield not broadened at level of anal opening, 88–97 between cribral pores. Para-anal setae 29, postanal 27–35.

Legs. Femur II av1 is strong spike, 33 long, shifted proximally to central point on segment making pv1-av1- av2 essentially straight ( Figs 23 , 27 ). Leg segment measures in Table 4 . No modified setae on tarsus II.

Etymology. From Euryclea, Ulysses’ nurse, who lived in the same house as Anticlea, Ulysses’ mother.

Remarks. Ulyxes euryclea was compared to five paratypes of the closely-related U. anticlea Domrow (QM S58721–4, 58739), which also occurs with Leadbeater’s possums. Both species share similar body size and an identical arrangement of apically bifid setae. However Ulyxes euryclea females differ from those of U. anticlea in always having only st5 on the genito-ventral shield, and this shield being relatively narrow with nearly parallel lateral edges in contrast to the broader, distinctly rounded shield of U. anticlea bearing st5, often Zv1 and sometimes also Jv1. U. euryclea has a distinctive gland pore posterolaterad px2 (as is in many Laelapidae ), whereas this pore is anterolaterad px 2 in U. anticlea . There are other consistent differences between the two species ( U. euryclea vs U. anticlea ): the number of fixed digit teeth (4 vs 2), number of denticles in deutosternal rows (8−13 vs 3−8), basal width of tritosternum (17–18 wide at origin, 10–11 at suture vs 27−30 wide at origin, 12−17 at suture), maximum width of the genito-ventral shield (193–215 vs 249–259), and distance between genitoventral and anal shields (0–8 vs 14−17).

Ulyxes euryclea has been recovered from natural and artificial nest cavities occupied by Glossy Black Cockatoos, Long-billed Corellas in Victoria and South Australia and also from nestboxes used solely by Leadbeater’s possums at Yellingbo, a lowland site. The other member of this genus recorded with Leadbeater’s possum is the closely-related U. anticlea ( Domrow, 1972b) .

The feeding biology of U. euryclea is unknown, but it is probably a nest-based predator of small invertebrates. Although U. euryclea has cheliceral digits the same length as the blood-feeding U. penelope Domrow , its dentition is stronger, with four teeth on the fixed digit ( Table 3 ). Also it is probably relevant that males retain chelate-dentate dentition (cf U. laertes ) and, in contrast to many putatively parasitic Ulyxes spp , it is found associated with a broad range of vertebrate species as listed above.

The complex sclerotised plate-like structure seen on the anterior pole of many of the eggs has not been detected in other Ulyxes spp. This structure appears to bear the pair of ramus sacculi (rs), opening into a pair of circular areas which may be the bilobed sacculus foemineus (sf, Fig. 20 ).

U. euryclea is superficially similar in its gracile setae, form of genito-ventral shield, and in general appearance to Nidilaelaps holdsworthi Shaw , which is only known from parrot nests in southern Australia. This species, along with Nidilaelaps annectans (Womersley) and U. euryclea , co-occur in Glossy Black cockatoo nests on Kangaroo Island, South Australia ( Shaw, 2012). However U. euryclea is instantly distinguishable from these species by those characters which diagnose Ulyxes spp , e. g. presence of apically bifid leg setae.

A female and two protonymphs in very poor, decayed condition were kerofloated from a nestbox housing Trichoglossus moluccanus Rainbow Lorikeet in Brisbane (nest 89). The female has similar dentition and anterior edge of sternal shield to U. euryclea , but it lacks a bifid seta on trochanter IV. More specimens are required before this population can be identified.

Figures

FIGURES 10–15. Ulyxes euryclea female. 10, dorsal shield, holotype, note prominent gland pores (gd) posterolaterad px2, scale = 100 µm; 11, epistome, nest 245, scale = 50 µm; 12, chelicera, axial view, paratype, nest 87, scale = 50 µm; 13, tritosternum, suture (s) marking top of tritosternal base, nest 87, scale = 50 µm; 14, gnathosoma, scale = 100 µm; 15, ventral idiosoma, holotype, scale = 100 µm.

FIGURES 16–21. Ulyxes euryclea female ex Glossy Black Cockatoo nest, Kangaroo Is, nest 245; 16, chelicerae, scale = 10 µm; 17, post-stigmatal plate showing gutter linking median (m) and posterior pore-like structures (only median visible in superficial SEM view) scale = 10 µm; 18, femur IV with apically bifid ad1 and ad2, scale = 10 µm; 19, habitus, ventral view, scale = 100 µm; 20, sclerotised plate-like structure at anterior pole of egg, rs = putative ramus sacculi, sf = putative sacculus foemineus, scale = 10 µm; 21, chelicera, anterior view showing apically divided tip, scale = 10 µm.

FIGURES 22–24. Ulyxes euryclea males: 22, venter, ex Leadbeater’s possum, Yellingbo, nest 486, scale = 100 µm; 23, femur II, ventral view, scale = 50 µm; 24, chelicerae, arrow indicates triangular tip of spermatodactyl, ex Long-billed Corella, Templestowe, nest 87, scale = 50 µm.

FIGURES 25–27. Ulyxes euryclea male ex Glossy Black Cockatoo nest, Kangaroo Island, nest 245: 25, ventral body, scale = 100 µm; 26, genital opening, scale = 10µm; 27, femur II, ventral view, scale = 10µm.

FIGURES 28–29. Ulyxes laertes male. 28, venter, Mt Clunie, nest 409, scale = 100 µm; 29, epistome, scale = 50 µm.

FIGURES 30–33. Ulyxes laertes. 30, male chelicera, Mt Clunie, nest 409, scale = 100 µm; 31, female chelicera, Tenison Woods Mt, scale = 100 µm; 32, male gnathosoma, nest 409, scale = 50 µm; 33, female gnathosoma, Tenison Woods Mt, scale = 50 µm.

FIGURES 52–57. Male chelicerae. 52, Ulyxes telemachus, Kioloa, NSW;53, U. penelope, Boho, Victoria; 54, U. ulixes Bauple SF, Queensland; 55, U. sisyphus, Timbillica; 56, U. euryclea; 57, U. laertes, Mt Clunie, NSW. All to same scale bar = 100 µm.