Indohya rixi Harvey &amp; Burger 2023, n. sp.
Creators: name: Harvey, Mark S.
name: Burger, Mieke A. A.
name: Abrams, Kym M.
name: Finston, Terrie L.
name: Huey, Joel A.
name: Perina, Giulia
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Pseudoscorpiones
Hyidae
Indohya
Indohya rixi

description: <i>Indohya rixi</i> Harvey &amp; Burger, n. sp. (Figs. 1–3, 5, 46, 47) urn:lsid:zoobank.org:act: 8A262014-510B-4838-B48E-24ACBA6752F6 <b>Material examined.</b> <i>Holotype male</i>. AUSTRALIA: <i>Western Australia:</i> Mesa C, 37.7 km W. of Pannawonica, 21°41′57″S, 115°57′49″E, 26 May 2013, haul net, J. Alexander (WAM T144193). <b>Diagnosis.</b> <i>Indohya rixi</i> most closely resembles <i>I. adlardi</i> and <i>I. sachsei</i> as all three possess 14 setae on the carapace arranged 4: 2: 4: 2: 2 and they lack eyes (Fig. 47A). It differs from them by its smaller size, e.g. chela (with pedicel) 1.055 (Ô) mm (1.865 –2.005 (&amp;female;) mm in <i>I. adlardi</i> and 1.22–1.27 (&amp;female;) mm in <i>I. sachsei</i>). It further differs from <i>I. sachsei</i> by trichobothrium <i>sb</i> being slightly closer to <i>st</i> than to <i>b</i> (ratio <i>sb–st</i> / <i>sb–b</i> = 1.16) [<i>sb</i> much closer to <i>st</i> than to <i>b</i> (ratio = 2.63) in <i>I. sachsei</i>]. There are no unique nucleotide substitutions in <i>COI</i> mtDNA that distinguish this species from all other species of <i>Indohya</i>. The single sequenced specimen differs from all other sequenced specimens of <i>Indohya</i> by 9.1–26.4% (Table 2). <b>Description (adult).</b> <i>Colour (Fig. 46):</i> pale yellow-brown. <i>Setae and cuticle:</i> setae long, mostly straight and acicular; most cuticular surfaces smooth and glossy. <i>Chelicera:</i> surface smooth; hand with 6 (Ô) setae, movable finger with 1 sub-medial seta, all setae acuminate; galea present, long, slender and slightly curved; fixed finger with 14 small (Ô), each approximately same size; movable finger with ca. 9 small (Ô) teeth, each approximately same size; with 2 dorsal and 1 ventral lyrifissures; lamina exterior absent; rallum with 6 blades, all blades with anterior spinules, basal blade shorter than others. <i>Pedipalp (Fig. 47B):</i> long and slender; trochanter smooth, 2.55 (Ô) ×; femur slightly broadened distally, smooth, without dorsal tactile seta, with 3 stout retrolateral setae near base, 6.55 (Ô) ×; patella slightly broadened distally, smooth, pedicel not strongly pronounced but basal portion slimmer than distal portion, with 4 lyrifissures situated basally on dorsal surface, including 3 long and 1 short lyrifissure, 4.24 (Ô) ×; chela (Fig. 47C): hand ovoid or slender, smooth, chela (with pedicel) 5.02 (Ô) ×, chela (without pedicel) 4.79 (Ô) ×, hand (without pedicel) 1.83 (Ô) × longer than broad, movable finger 1.60 (Ô) × longer than hand (without pedicel). Fixed finger with 8 trichobothria, <i>eb</i>, <i>esb</i> and <i>isb</i> in straight row at base of finger, <i>ib</i> situated dorsally at the end of the chelal hand, <i>isb</i> at the basal end of the fixed finger, <i>ib</i> situated on dorsum of chelal hand, <i>it</i> closer to <i>et</i> than to <i>est</i>, <i>et</i> slightly distal to <i>it</i>; movable finger with 4 trichobothria, <i>sb</i> closer to <i>b</i> than to <i>st</i>, <i>st</i> situated much closer to <i>t</i> than to <i>sb</i>, ratio <i>sb–st</i> / <i>sb–b</i> = 1.81 (Ô), <i>t</i> acuminate. Both fingers straight in lateral view. Fixed finger smooth, movable finger with several retrolateral granulations basally. Chelal teeth (Figs. 47D, E) juxtadentate, fixed finger with 62 (Ô) teeth, teeth 1–3, 47–48, 50–52 pointed, remainder rounded, movable finger with ca. 25, low teeth or triangular, strongly retrorse teeth. Venom apparatus present only in movable chelal finger, venom duct long, terminating in nodus ramosus between <i>sb</i> and <i>st</i>. <i>Cephalothorax:</i> carapace (Fig. 47A) sub-rectangular; smooth; anterior margin slightly convex; epistome absent; lateral margins slightly convex; posterior margin straight; 1.26 (Ô) × longer than broad; with 14 setae arranged 4: 2: 4: 2: 2 (Ô); without furrows; eyes absent. Manducatory process distally triangular, with 2 distal setae; pedipalpal coxa with 7 (Ô) additional setae. Coxa I with anterior margin not modified; chaetotaxy of coxae I–IV: Ô, 4: 4: 3: 4. <i>Legs:</i> femora I and II much longer than patellae I and II, respectively; femora I and II with basal swelling; femora I and II each with 2 slit sensilla, each directed transversely; junction between anterior femora and patellae perpendicular; junction between posterior femora and patellae slightly oblique; femora III and IV much smaller than patellae III and IV, respectively; femur + patella IV 4.96 (Ô) × longer than broad; metatarsi shorter than tarsi; subterminal tarsal seta acuminate; claws smooth, arolium slightly shorter than claws; arolium not divided. <i>Abdomen:</i> tergites not divided; tergal chaetotaxy Ô, 4: 4: 6: 6: 6: 6: 6: 5: 6: 4: 4: 2; arranged in single rows; sternal chaetotaxy Ô, 16: (2) 15 [2 + 2] (2): (2) 4 (2): 8: 6: 6: 6: 6: 6: 4: 2; posterior tergites and sternites with several tactile setae; medial sternites without suture line; pleural membrane uniformly granulate; without setae; stigmatic helix present. <i>Genitalia:</i> male: lateral genital sacs large and ovoid; median genital sac short and ovoid; ejaculatory duct atrium large and rounded; dorsal apodeme wing-like; without a pair of large dorsal genital sacs; with 2 pairs of setae within genital atrium. <i>Dimensions (mm):</i> male holotype (WAM T144193). Body length (excluding chelicerae) 1.41. Pedipalp: trochanter 0.255 / 0.100, femur 0.720 / 0.110, patella 0.530 / 0.125, chela (with pedicel) 1.055 / 0.210, chela (without pedicel) length 1.005, chelal hand (without pedicel) length 0.385, movable finger length 0.615. Carapace 0.490 / 0.390. Leg IV: femur + patella 0.505 / 0.120, tibia 0.350 / 0.065, metatarsus 0.100 / 0.050, tarsus 0.315 / 0.045. <b>Distribution and remarks.</b> <i>Indohya rixi</i> has only been found from subterranean habitats in Mesa C, in the western Pilbara (Fig. 5). The species was previously known by WAM identification code <i>Indohya</i> ‘PSE170’. There are no observable morphological differences between <i>I. rixi</i> and <i>I. adlardi</i>, other than size, e.g. the chela length (with pedicel) is 1.055 mm in the sole male of <i>I. rixi</i>, and 1.865 –2.005 mm in six females of <i>I. adlardi</i>. Although male hyids are generally slightly smaller than females, the size difference between this species pair is considerable with the females of <i>I. adlardi</i> being nearly twice as large as the male of <i>I. rixi</i>. Furthermore, they occur in adjacent but separate mesas in the Robe River Valley (Fig. 5). <b>Conservation assessment</b>. Mesa C is a small mesa in the Robe River Valley which is scheduled to be developed into an iron ore mine in which the vast majority of the subterranean habitat will be extracted. Like other troglobitic arthropods that occur in the subterranean environment of Mesa C, it is highly unlikely that <i>I. rixi</i> occurs in any nearby environments, as these mesas are occupied by other species of <i>Indohya</i>. The combination of small distribution and potential loss of available habitat if the mine commences suggests that this species is Vulnerable (B2ab[iii]) using the criteria developed by the International Union for Conservation of Nature (2012). <b>Etymology.</b> This species is named for our friend and colleague Mike Rix in appreciation for his contributions to systematic research.
description: Published as part of <i>Harvey, Mark S., Burger, Mieke A. A., Abrams, Kym M., Finston, Terrie L., Huey, Joel A. &amp; Perina, Giulia, 2023, The systematics of the pseudoscorpion genus Indohya (Pseudoscorpiones: Hyidae) in Australia, pp. 1-119 in Zootaxa 5342 (1)</i> on pages 86-89, DOI: 10.11646/zootaxa.5342.1.1, http://zenodo.org/record/8323879