Cunaxa minidiscondyla, Corpuz-Raros & Naredo & Garcia, 2019

Corpuz-Raros, Leonila A., Naredo, Jeremy C. B. & Garcia, Rufino C., 2019, Additional contributions to the knowledge of Philippine predatory mites mainly of the subfamilies Cunaxinae and Cunaxoidinae (Acari: Prostigmata: Cunaxidae), Acarologia 59 (1), pp. 134-151 : 138-142

Cunaxa minidiscondyla sp. nov. ( Figs 1 – 4 )

Zoobank: 4B17779F-F0C5-4D6C-8DDE-6729B4596189

Diagnosis

Relatively large species, soft-bodied, entirely striated, with an ill-defined propodosomal shield and without hysterosomal shield; palp long and slender, with a small disc-like apophysis dorsoapically on inner margin of telofemur, two spine-like setae dorsally on genu, and one long spine dorsally on inner third of tibiotarsus; long and smooth hysterosomal setae; number of setae on basifemora 4-4-3-1, and on telofemora 5-5-4-4.

Description

Female — Rather large, body length x width 884 x 440; soft-bodied, entirely striate including an ill-defined propodosomal shield. Legs relatively short, IV longest, slightly over ½ of body length.

Gnathosoma ( Figure 1 a-c) — Subcapitulum ( Figure 1a ) 204 long, about ¼ of total body length, covered by coarse broken striae running transversely at base and finer striae lengthwise distally; four pairs of subcapitular setae, hg1 24, hg2 37, hg3 68, hg4 37; two pairs of short adoral setae present. Palp ( Figure 1b ) 262 long and slender, 1¼ times as long as gnathosoma and ends in a very small claw; segments scarcely ornamented with large spinules; basifemur with one short sts dorsally; telofemur with one short sts dorsally on outer margin and one small (length x width about 3 x 3) disc-shaped apophysis dorsodistally on inner margin, close to its division from the genu; genu with two spls dorsally and one thin sts ventrally; tibiotarsus long and thin, about half the length of palp, with two long and thin sts and one long (22) spls on basal third of segment, and two short sts dorsally on distal third. Chelicera ( Figure 1c ) 190 long, three-segmented and ends in a strong claw, first segment densely papillate, second segment striate on inner half; cheliceral seta present, arising near base of claw.

Idiosoma ( Figure 2 a-b) — Idiosoma 608 long, 440 wide, entirely striated. Propodosomal shield ill-defined, discernible only by the flat broken striae running across the shield; with two pairs of very long, plumose trichobothria vi and sce, and two sts, ve and sci; vi arising closely (distance vi-vi 37) and separated by a distinct membranous lobe, 357 long, slightly over ½ the length of idiosoma; sce 435 long, about ¾ the length of idiosoma, arising at a distance (197) that is about five times that between vi; ve very short, 10 long, arising close to sce; sci much longer (78) and thicker, arising equidistant from each other (distance sci-sci and sci-sce 68) and in the same transverse line as the posterior trichobothria sce. Hysterosoma without median plate, finely striate-papillate up to level of setae f1 and becoming coarser with larger round papillae posteriorly. Hysterosomal setae smooth, their lengths as follows – c1 82, c2 65, d1 61, e1 58, f1 68, h1 61. Distances between median setae decreasing posterad: c1-c1 136, c2-c2 241, d1-d1 143, e1-e1 112, f1-f1 37, h1-h1 24; ratio of their mutual distance to their length: c1 1.7, c2 3.7, d1 2.3, e1 1.9, f1 0.5, h1 0.4. Cupules not readily discernible against striations of hysterosoma.

Venter finely striate-papillate; five pairs of setae on ventral membrane, viz., one propodogastral, three hysterogastral and one paragenital. Genital plates striate with small papillae on inner side; four pairs of setae present, g1 and g4 arising laterally near outer margin, g2 and g3 near inner margin of shield. Anal plates finely striate-papillate, with one pair of anal (ps1) setae; one pair of paraanal (pa) setae also present, flanking the anal plates.

Legs ( Figure 3 a-d) — Rather short, femora thick, tarsi very long, almost as long as basal free segments taken together, tapering, without distinct terminal lobes and end in two claws and rayed empodium; femoral segments not clearly separated, basifemora covered with flat, coarse striae, telofemora and other leg segments densely covered with spine-like papillae. Lengths of legs: I 456, II 428, III 469, IV 509. Chaetotaxy of leg segments I-IV: coxae 3-1-3-2; trochantera 1-1-2-1; basifemora 4-4-3-1; telofemora 5-5-4-4; genua 4 sts, [1 asl, 1 sts], [1 bsl, 1 sts], 1asl –

5 sts, 2 asl – 5 sts, 1 asl – 5 sts, 1 asl; tibiae 4 sts, [1 long bsl, 1 mst], 1 short bsl – 5 sts, 1 short bsl – 5 sts, 1 thick bsl – 4 sts, 1T; tarsi 21 sts, [2 bsl, 1 mst], 2 bsl, 1 dtsl, 2 tsl – 21 sts, 1 long basally inflated bsl, 1 dtsl – 23 sts, 1 dtsl – 21 sts, 1 dtsl.

Tritonymph ( Figure 4 a-e) — Essentially like adult female including the presence of an ill-defined propodosomal shield and entirely striate hysterosoma, chaetotaxy of hysterosomal dorsum and palps, and the presence of a very small, disc-like apophysis dorsoapically on inner margin of palp telofemur. It differs by being smaller (length x width 619 x 272 vs 884 x 440), presence of only three pairs of setae (hysterogastral) on ventral membrane of idiosoma, and the chaetotaxy of some leg segments as detailed below. Measurements: gnathosoma160, palp 172, chelicera 150; propodosomal setae vi 255, ve not observed, sci 54, sce 309; hysterosomal setae c1 78, c2 58, d1 48, e1 34, f1 37, h1 31.

Chaetotaxy of leg I-IV segments — as in female except for basifemora 4-4-3-0 (vs 4-4-3-1); genu I with only one duplex of 1 bsl and 1 sts (vs. two duplexes of asl-sts and bsl-sts); tarsus I with one duplex of bsl-sts (vs. triplex of 2 bsl-1 sts); and the number of sts on tarsi I-IV unknown-20-18-15 (vs. 21-21-23-21).

Material — Holotype female, locality 7; paratype: one tritonymph, locality 34; non-type: one female, locality 5.

Etymology — The specific name denotes the small, disc-like apophysis or condyle on the palp telofemur which readily separates this species from its congeners.

Remarks — The new species resembles some Cunaxa species with short and non-pointed apophysis on the palp telofemur, viz., C. carina Den Heyer, 1979 ( South Africa) where this apophysis is truncated, C. magee Smiley, 1992 where it is broadly conical with acutely rounded tip, and C. neogazella Smiley, 1992 ( USA) where it is blunt and fingerlike (vs. disc-like in C. minidiscondyla ). In all these species, leg basifemoral chaetotaxy is 4-4-3-1; C. minidiscondyla differs in having 5-5-4-4 setae on the telofemur, vs. 4-4-4- 4 in the named non-Philippine species.

The new species also resembles Cunaxa setirostris (Hermann, 1804) (as per redescription of the species based on the neotype designated by Den Heyer and Sergeyenko, 2009) by the presence of two spls on palp genu and one spls on palp tibiotarsus but the palp telofemoral apophysis is pointed and spine-like in the latter species. In addition, C. minidiscondyla has 4-4 sts on basifemora I-II or a total of 8-8 for the basi- and telofemur taken together as one femoral segment I-II. On the other hand, Den Heyer and Sergeyenko (2009) indicated a 7-7 femoral I-II chaetotaxy for C. setirostris and later, in a study of Iranian Cunaxinae , Den Heyer, et al. (2011) showed 3-3 sts on basifemora I-II, separate from the telofemora with 4-4 sts ( Figs. 2E & F ). The presence of 3 sts on basifemur I is one of the main key characteristics used by Skvarla et al. (2014) to separate C. setirostris from other species of Cunaxa .

Figures

Figure 1 Cunaxa minidiscondyla n. sp., female: a – subcapitulum; b – palp; c – chelicera. Scale bar 50 µm.

Figure 2 Cunaxa minidiscondyla n. sp., female idiosoma: a – dorsum; b – venter. Scale bar 100 µm.

Figure 3 Cunaxa minidiscondyla n. sp., female: a – Leg I; b – Leg II; c – Leg III; d – Leg IV. Scale bar 100 µm.

Figure 4 Cunaxa minidiscondyla n. sp., tritonymph: a – venter of idiosoma; b – leg I (trochanter to base of tarsus); c – leg II; d – leg III; e – leg IV. Scale bar 100 µm.