Molothrognathus venustus ( Khaustov & Kuznetsov, 1997 )

Khaustov, Alexander A., 2024, A new species and a new record of Caligonellidae (Acari: Raphignathoidea) from Russia, Persian Journal of Acarology 13 (1), pp. 1-11 : 5-9

Molothrognathus venustus ( Khaustov & Kuznetsov, 1997) ( Figs. 4–7 )

Caligonella venusta Khaustov and Kuznetsov, 1997: 80

Molothrognathus venusta : Doğan 2003, 69

Molothrognathus artvinensis Koç and Ayyıldız, 1997: 47 , synonymy by Doğan 2003, 69 Molothrognathus venustus : gender agreement, corrected here under art. 34.2 of ICZN

Diagnosis

Female – Dorsal shield absent; idiosomal striae very thick, double; three pairs of aggenital setae; three pairs of pseudanal setae; dorsal idiosomal setae short, subequal; seta vs of tarsus I absent; seta p” of tarsus II absent; tibia I with one solenidion; stylophore elliptical.

Redescription

Female ( Figs. 4–6 ) – Length of idiosoma 390‒410, width 205‒210.

Idiosomal dorsum ( Fig. 4A ) ‒ Ovate. Dorsal idiosomal striae thick, usually double; dorsal shield absent. Two pairs of subequal ocelli located posterolaterad setae sci. Cupuli ia, im and ip large, almost round; ia located just posteromesad posterior ocellus, im anterolaterad d, and ip posterolaterad f. All dorsal idiosomal setae short, subequal, smooth and pointed. Anal valves located dorsoterminal, with three pairs of pseudanal setae; setae ps3 located dorsally. A pair of longitudinal, oblique rows of tiny subcuticular sclerites situated laterad setae c1 and d. Lengths of dorsal setae: vi 19‒20, ve 17‒18, sci 19‒23, sce 20‒21, c1 18‒19, c2 19‒20, d 17‒18, e 17, f 15‒16,

h1 15‒17, h2 16, ps1 8, ps2 12, ps3 13.

Idiosomal venter ( Fig. 4B ) ‒ Ventral idiosoma striated, without plates. All ventral setae smooth and pointed. Setae 3a located on the margin of coxisternal fields III. Coxisternal fields I‒IV sparsely punctate. Three pairs of aggenital and one pair of genital setae; cupuli ih located anterolaterad ag3. A pair of almost parallel rows of small subcuticular sclerites situated laterad setae 4a. Lengths of ventral setae: 1a 25, 1b 22‒23, 1c 13‒14, 2c 13‒14, 3a 25‒26, 3b 14‒15, 4a 18‒19, 4c 13‒14, ag1 15‒16, ag2 12‒13, ag3 11‒13, g 12.

Gnathosoma ( Fig. 5 ) ‒ Stylophore short and wide, elliptical in shape; longitudinally striated in basal half and punctate in distal one, its width 67‒69; peritremes tubular, typical for the genus, their anterior ends situated near anterior margin of stylophore; peritremes inside with fine striae; cheliceral levers large, bean-shaped, about 1.5 times shorter than cheliceral stylets. Palpal supracoxal setae (ep) very small and located in deep depression with terminal pore; palpal chaetotaxy: Tr 0, Fe 1 (d), Ge 1 (d), Ti 3 (d, l’, l”), Ta 7(1) (ba, bp, va, acmϛ, ul’ϛ, ul”ϛ, sulϛ, ω); tibial claw large, slightly hooked; all palpal setae smooth, eupathidia acmϛ, ul’ϛ, ul”ϛ, and sulϛ distinctly widened distally, with four subapical flat lobes; seta va usually blunt-tipped, sometimes distinctly widened distally, with four subapical flat lobes ( Fig. 2A ); seta bp slightly flattened and blunt-tipped distally; seta ba pointed; solenidion ω very small, rod-shaped. Subcapitulum striated in basal half and punctate in distal one; all subcapitular setae smooth and pointed. Rostrum of subcapitulum short and wide, almost V-shaped split between setae or2. Lengths of subcapitular setae: m 30‒32, or1 11‒12, or2 11‒12, length of palptarsal solenidion ω 3, length of cheliceral stylet 28.

Legs ( Fig. 6 ) ‒ Lengths of legs (excluding claws): I 235, II 180‒185, III 200‒210, IV 225‒230. Leg I ( Fig. 6A ) longer than other legs. Leg setation: Tr 1 (v’), Fe 2 (d, bv”), Ge 6 (d, l’, l”, v’, v”, k), Ti 5(1) (d, l’, l”, v’, v”, φp), Ta 14(1) (ft’, ft”, tc’ϛ, tc”ϛ, p’ϛ, p”ϛ, a’, a”, u’, u”, pv’, pv”, pl’, pl”, ω). Supracoxal seta of leg I (el) located in deep depression with terminal pore; all leg setae smooth; seta vs absent, setae (tc) and (p) eupathid-like, blunt-tipped, with very small subapical projections, other leg setae pointed; solenidion ω 8 digitiform, solenidion φp 10‒11 baculiform; seta k 3 weakly clavate. Leg II ( Fig. 6B ). Leg setation: Tr 1 (v’), Fe 2 (d, bv”), Ge 4 (d, l’, l”, v’), Ti 5 (d, l’, l”, v’, v”), Ta 9(1) (ft’, tc’, tc”, a’, a”, u’, u”, pv’, pv”, ω). All leg setae smooth and pointed; seta p”ϛ absent; solenidion ω 6‒7 digitiform. Leg III ( Fig. 6C ). Leg setation: Tr 1 (v’), Fe 2 (d, ev’), Ge 2 (d, v’), Ti 4 (d, l”, v’, v”), Ta 8 (tc’, tc”, a’, a”, u’, u”, pv’, pv”). All leg setae smooth and pointed. Leg IV ( Fig. 6D ). Leg setation: Tr 1 (v’), Fe 2 (d, ev’), Ge 2 (d, v’), Ti 4 (d, l”, v’, v”), Ta 8 (tc’, tc”, a’, a”, u’, u”, pv’, pv”). All leg setae smooth and pointed.

Male ( Fig. 7 ) – Idiosoma narrower posteriorly than in female. Length of idiosoma 285, width 185.

Idiosomal dorsum ( Fig. 7A ) ‒ Striation and setal lengths similar with those of female, except presence of almost smooth pygidial shield with setae h1 and h2. Only two pairs of pseudanal setae. Lengths of dorsal setae: vi 15, ve 13, sci 16, sce 18, c1 16, c2 16, d 15, e 14, f 14, h1 11, h2 14, ps1 11, ps2 12. Aedeagus weakly sclerotized, long, and slightly curved.

Idiosomal venter ( Fig. 7B ) ‒ Ventral idiosoma completely striated. Two pairs of aggenital setae; genital setae absent. Other characters as in female. Lengths of ventral setae: 1a 18, 1b 19, 1c 13, 2c 13, 3a 22, 3b 12, 4a 16, 4c 15, ag1 16, ag2 16.

Gnathosoma as in female. Width of stylophore 52, lengths of setae: m 22, or1 10, or2 10, length of palptarsal solenidion ω 3.

Legs as in female, except absence of seta v’ on trochanters I‒IV. Lengths of legs: I 195, II 155,

III 165, IV 185. Solenidion ω I 5, φp 7, ω II 5, seta k I 3.

Immatures unknown.

Material examined

Two females, one male, Russia, Tyumen Oblast, city of Tyumen, Gagarin Park , moss on soil, 57° 10' N, 65° 36' E, 28 March 2023, collected by A.A. Khaustov.

Remarks

Molothrognathus venustus was described from Ukraine ( Khaustov and Kuznetsov 1997). Doğan (2003) synonymized M. artvinensis Koç and Ayyıldız, 1997 , described from Turkey, under M. venustus . The original description of M. venustus as well as description of M. artvinensis lacking detailed illustrations of some gnathosomal structures and legs. Male was not depicted. The comparison of specimens collected in Western Siberia with the type material of M. venustus confirms their identity. Using DIC revealed an unusual shape of some setae on palptarsus, which were missed in original description.

Figures

Figure 2. Neognathus beshtauiensis sp. nov., female – A. Gnathosoma, dorsal aspect; B. Subcapitulum.

Figure 4. Molothrognathus venustus (Khaustov & Kuznetsov, 1997) (female) – A. Idiosomal dorsum; B. Idiosomal venter.

Figure 5. Molothrognathus venustus (Khaustov & Kuznetsov, 1997) (female) – A. Gnathosoma, dorsal aspect; B. Subcapitulum.

Figure 6. Molothrognathus venustus (Khaustov & Kuznetsov, 1997) (female) – A–D. Right legs I-IV respectively, dorsal aspect.

Figure 7. Molothrognathus venustus (Khaustov & Kuznetsov, 1997) (male) – A. Opisthosoma, dorsal aspect; B. Opisthosoma, ventral aspect.