Galumnella subiasi, Kolesnikov & Leonov, 2024

Kolesnikov, Vasiliy B. & Leonov, Vladislav D., 2024, A new species of Galumnella (Acari, Oribatida, Galumnellidae) from Vietnam, Zootaxa 5556 (1), pp. 242-251 : 243-249

Galumnella subiasi sp. nov.

( Figs 1–5 )

Material examined. Holotype (female) and 2 paratypes (females) at the coordinates 12.1854º N, 108.6789º E .

Etymology. The new species is named in honor of Luis S. Subías, the renowned acarologist and specialist on oribatid mites, who made a profound contribution to the study of mites.

Diagnosis. Body size: 360–364 × 271–275. Body surface with small, sparse foveolae; in addition, notogaster with a reticular pattern of large, often rectangular cells; pteromorph, middle part of prodorsum and ventral shield with a reticular pattern of medium-sized irregular cells (larger at the base of the pteromorph and between the anal and genital openings, smaller at the front of the pteromorph and on the prodorsum). Rostrum rounded. Lamellar and sublamellar lines present, parallel. Interlamellar region with transverse ridge. Rostral and lamellar setae of medium length, interlamellar seta minute; all setae setiform, thin. Bothridial setae long, setiform, slightly expanded in the middle, unilaterally heavily spinose. Notogastral, epimeral and anogenital setae short, setiform, smooth. Adanal seta ad 3 located anterior to anal aperture, ad 1, ad 2 and ad 3 not located in straight line. Median pore and postanal porose area absent. Posterior part of notogaster rounded. Circumpedal carina long, reaching the middle part of epimeron I. All leg tarsi with three claws.

Description of adult. Measurements. Body length: 361 (holotype: male), 360 and 364 (two paratypes); notogaster width: 275 (holotype), 271 and 275 (two paratypes).

Integument ( Figs 1–5 ). Body color dark brown. Body surface (including subcapitular mentum and genital and anal plates) sparsely foveolate (diameter of foveola small, up to 2). In addition, notogaster, pteromorph, middle part of prodorsum and ventral shield with a reticular pattern of medium and large cells; cells on central part of notogaster and between genital and anal openings is large size, often rectangular; cells on basal part of pteromorph and posterior part of notogaster is middle size; cells on anterior and lateral part of pteromorph and prodorsum in small size. Between the genital opening and the gnathosoma there is a strong granulation along the medial line, surrounded by a reticular ornament with elongated cells.

Prodorsum ( Figs 1 , 3 , 5B ). Rostrum protruding, rounded. Lamellar and sublamellar lines thin, parallel, curving backwards at ventral end. Interlamellar region with thin transverse ridge. Rostral (29) and lamellar (11) setae setiform, thin, ro barbed, le smooth; ro thicker than le. Insertion of lamellar seta located close to L. Interlamellar seta minute (2), setiform, thin, smooth. Bothridial seta (80) setiform, slightly expanded in the middle, unilaterally heavily spinose, directed posterolaterad. Exobothridial seta and dorsosejugal porose area absent.

Notogaster ( Figs 1 , 3 , 5A, D ). Dorsosejugal suture present, simple. With 10 pairs of short (4–6), setiform, thin, smooth setae. Median pore absent. Posterior part of notogaster rounded. Dorsolateral pore, opisthonotal gland opening and all lyrifissures distinct (except ia not observed).

Gnathosoma ( Figs 3B–D ). Size of subcapitulum: 75 × 58. All subcapitular setae (a: 12; m: 4; h: 4) setiform, smooth; a thickest, h thinnest. Both adoral setae not observed. Length of palp: 51. Postpalpal seta absent. Length of chelicera: 88. Cheliceral setae cha and chb represented by alveolus.

Epimeral and lateral podosomal regions ( Figs 2 , 3A , 5C ). Epimeral setal formula: 1-1-3-3. All setae (4–6) setiform, thin, smooth. Pedotecta I and II rounded in ventral aspect. Discidium triangular. Circumpedal carina long, reaching of the middle part of epimere I.

Anogenital region ( Figs 2 , 3A , 5E ). Genital, aggenital, anal, and adanal setae (4–6) setiform, thin, smooth. Anterior edge of genital plate with three setae. Aggenital seta located between genital and anal apertures, closer to the former. Adanal lyrifissure located anterolateral and distanced from anal plate. Adanal seta ad 3 located anterior of anal aperture, ad 1, ad 2 and ad 3 not located in straight line, distance between adanal setae ad 2 – ad 3 longer than ad 1 – ad 2. Postanal porose area absent.

Legs ( Figs 4 ). Tridactylous. Middle claw strong, smooth, without ventrobasal tubercle; lateral claws thin, smooth. Porose area on all femora and on trochanters III, IV slightly visible. Formulas of leg setation and solenidia: I (1-4-3-4-20) [1-2-2], II (1-4-3-4-15) [1-1-2], III (1-2-1-3-15) [1-1-0], IV (1-2-2-3-12) [0-1-0]; homology of setae and solenidia indicated in Table 1 . Famulus of tarsus I short, erect, blunt-ended, inserted anterior to solenidion ω 1. Seta s of tarsus I eupathidial, located before setae a. Seta l’ on genu IV thick, thorn-like, spinose. Solenidia ω 1 and ω 2 on tarsi II bacilliform, other solenidia setiform. Solenidion ω 1 longer and thicker than ω 2 on tarsus I. Solenidion on tibia IV inserted in the middle part of the segment.

Remarks. The new species is most similar to G. geographica Mahunka, 1995 in of the presence of a cellular pattern on the notogaster, ventral shield, prodorsum, and pteromorph. Both species also share a similar form of bothridial setae (setiform, slightly expanded in the middle, unilaterally heavily spinose), the location of the adanal lyrifissure located anteriolateral to the anal plate and distanced from it, three claws on the leg tarsi. However, in the new species, the cells in the central part of the notogaster are larger and more sparsely distributed (with three cells between lm in the new species vs. five in G. geographica ); the anterior edge of the pteromorph has numerous small cells similar to those on the prodorsum (vs. the pteromorph being evenly covered with a homogeneous mesh of irregularly shaped cells in G. geographica ); a distinct interlamellar ridge is present (vs. absent in G. geographica ); adanal seta ad 3 is located anterior to the anal aperture (vs. paraanal in G. geographica ); the distance between adanal setae ad 2 – ad 3 is distinctly longer than ad 1 – ad 2 (vs. the distance between adanal setae ad 1 – ad 2 being slightly longer than ad 2 – ad 3 in G. geographica ); and the postanal porose area is absent (vs. present in G. geographica ). The new species also strongly resembles G. woschitzi Balogh, 1970 in terms of the ornamentation of the notogaster (large cells), the form of the bothridial setae (setiform, slightly expanded in the middle, unilaterally heavily spinose), the presence of a distinct interlamellar ridge, and the positioning of adanal seta ad 3. However, the new species significantly differs from G. woschitzi by having a cellular ornamentation on the pteromorph and prodorsum (vs. absent in G. woschitzi ); lamellar setae are setiform and clearly visible (vs. not visible, alveolar in G. woschitzi ); and a drop-shaped subcapitulum (vs. trapezoid-shaped in G. woschitzi ).

Figures

FIGURE 1. Galumnella subiasi sp. nov., adult, dorsal view. Scale bar 100 μm.

FIGURE 2. Galumnella subiasi sp. nov., adult, ventral view (gnathosoma and legs not shown). Scale bar 100 μm.

FIGURE3.Galumnellasubiasisp.nov., adult:A—lateralview(pteromorph,gnathosoma andlegsnot shown);B—subcapitulum, ventral view; C—chelicera, right, antiaxial view; D—palp, right, antiaxial view. Scale bar 100 (A), 50 (B–D) μm.

FIGURE 4. Galumnella subiasi sp. nov., adult: A—leg I (trochanter omitted), right, antiaxial view; B—leg II (trochanter omitted), right, antiaxial view; C—leg III, right, antiaxial view; D—leg IV, left, antiaxial view. Scale bar 100 μm.

FIGURE 5. Galumnella subiasi sp. nov., adult, DIC images: A—notogaster, dorsal view; B—anterior part of notogaster an prodorsum, dorsal view; C—genital region, ventral view; D—pteromorph, lateral view; E—anal region, ventral view. Scale bar 100 μm.