Parabelbella pseudoinaequipes, Ermilov & Ryabinin, 2020

Ermilov, Sergey G. & Ryabinin, Nikolay A., 2020, Сontribution to the knowledge of Parabelbella (Acari, Oribatida, Damaeidae): description of two new species from Russia and the U. S. A., redescription of P. inaequipes (Banks, 1947) and a key to known species, Zootaxa 4860 (3), pp. 352-374 : 360-366

Parabelbella pseudoinaequipes sp. nov.

( Figs 7–12 )

Material examined. Holotype (male) and 15 paratypes (13 males and two females): U.S.A., New York Allegany Co., nr. Belmont , mixed red pine, oak, hemlock litter, 25.XI.1973 (collected by D.P. Schwert).

Type deposition. The holotype is deposited in the collection of the USNM ; two paratypes are deposited in the collection of the SMNH; 13 paratypes are deposited in the collection of the TSUMZ. All specimens are preserved in ethanol with a drop of glycerol.

Diagnosis. Body size: 381–415 × 232–249. Propodolateral apophysis and all prodorsobasal tubercles absent. Rostral and lamellar setae long, setiform, barbed. Interlamellar seta long, stiff, erect, barbed. Bothridial seta very long, flagellate, smooth. Dorsal notogastral setae long, stiff, elongate crescent (la, lm distinctly barbed, c 1, c 2, lp, h 3 usually with one or two small barbs, rarely roughened, h 2, h 3 roughened), p 1 – p 3 short, thinner and less stiff, roughened. Setae c 1 directed anteriad. Distance c 1 – c 1 shorter than that of c 1 – c 2. Distance lm–lp longer than that of la–lm and lp–h 3. Parastigmatic apophysis Sa thorn-like, Sp tubercle-like. Epimeral and anterior pair of ventrosejugal tubercles absent. Anterior median ventral tubercle and posterior pair of ventrosejugal tubercles present, simple. Discidium triangular. Epimeral and anogenial setae setiform, roughened, seta 3b inserted on Vp. Leg femur III with four setae.

Description. Measurements. Body length: 381 (holotype), 381–415 (15 paratypes); notogaster width: 232 (holotype), 232–249 (15 paratypes). No clear differences between males and females in body size.

Integument ( Figs 10 A–D). Body color brown. Surface of body and legs sculptured (microtuberculate), partially covered by layer of cerotegument, which is represented by tuberculate and bacillar (sometimes also filamentous) structures.

Prodorsum ( Figs 7A, C ; 10A, C ; 11A, B ). Rostrum rounded. Prodorsal tectum, propodolateral apophysis, anterobothridial ridge and all prodorsobasal tubercles absent. Median part of interbothridial region with slightly visible muscle sigillae. Rostral (53–57) and lamellar (61–69) setae setiform, barbed, directed anteromediad. Interlamellar seta (41–45) stiff, erect, barbed, directed posteriad. Bothridial seta (225–233) flagellate, smooth. Exobothridial seta (20–24) setiform, thin, slightly barbed.

Notogaster ( Figs 7 A–C; 8A, C; 9A, C; 12A, B). Oval. Exuvial scalps usually absent (present in two paratypes). Eleven pairs of notogastral setae of light color, stiff, elongate crescent, but posterior setae (p 1 – p 3) thinner and less stiff. Setae la, lm (41–45) distinctly barbed, c 1, c 2, lp, h 3 (36–45) usually with one or two small barbs, rarely roughened, h 2, h 3 (36–41), p 1 – p 3 (20–24) roughened. Dorsal notogastral setae inserted in two parallel rows, c 1 directed anteriad, c 2 directed anterolaterad, other setae directed posteriad. Mutual distance between setae c 1 – c 1 shorter than that of c 1 – c 2. Distance between insertions of seta lm–lp distinctly longer than that of la–lm and lp–h 3. All notogastral lyrifissures, opisthonotal gland opening, circumgastric scissure and circumgastric sigillar band distinct.

Gnathosoma ( Fig. 10B ). Subcapitulum longer than wide (90–98 × 69–77). Three pairs of subcapitular setae (a, 20–24; m, 28–32; h, 24–28) setiform, slightly barbed. Two pairs of adoral setae (8–12) setiform, thin, roughened. Palp (82–86) with setation 0-2-1-3-9(+ω). Solenidion of palptarsus bacilliform, appressed to palptarsal surface. Postpalpal seta (6) spiniform, smooth. Chelicera (90–94) with two setiform setae, cha (28) barbed, chb (16) shortly ciliate unilaterally in mediodistal part. Trägårdh’s organ of chelicera elongate triangular.

Lateral podosomal and epimeral and regions ( Figs 7B, C ; 9B, C ; 10A , D–F). Parastigmatic apophysis Sa thorn-like, elongate triangular, Sp tubercle-like. Both pairs of epimeral tubercles absent. Anterior pair of ventrosejugal tubercles absent, posterior pair present, simple. Anterior median tubercles present, simple, posterior absent. Discidium triangular. Epimere I without median hollow (ring-like internal structure in light microscope). Epimeral setal formula 3-1-3-4. Epimeral setae (1a, 1c, 2a, 3a, 20–24; 1b, 3b, 3c, 4a, 4b, 4c, 4d, 28–36) setiform, roughened, seta 3b inserted on ventrosejugal tubercle Vp.

Anogenital region ( Figs 7B, C ; 9B, C ; 10A ). Six pairs of genital, one pair of aggenital, two pairs of anal and three pairs of adanal setae similar in length (20–24), setiform, roughened. Adanal lyrifissure diagonal, located close to anal plate. Adanal seta ad 3 located posterolaterally to adanal lyrifissure.

Legs ( Figs 8A, B ; 9A, B ; 10 A–C; 11A). Legs I and III similar to body in length approximately, legs II shorter than body length, leg IV longer than body length ( Table 3 ). Claw of all legs comparatively small, thin, smooth. Dorsoparaxial porose area on femora I–IV and on trochanters III and IV well visible. Formulas of leg setation and solenidia: I (1-7-4-4-20) [1-2-2], II (1-6-4-4-17) [1-1-2], III (2-4-3-3-17) [1-1-0], IV (1-4-3-3-14) [0-1-0]; homologies of setae and solenidia indicated in Table 2. Solenidion and coupled seta on genua I–III similar in length approximately.

Etymology. The specific name pseudoinaequipes refers to the similarity of the new species and Parabelbella inaequipes ( Banks, 1947) .

Remarks. Parabelbella pseudoinaequipes sp. nov. is morphologically most similar to Parabelbella inaequipes ( Banks, 1947) in the absence of propodolateral apophysis, all prodorsobasal tubercles and ventrosejugal tubercles Va, and the presence of ventrosejugal tubercles Vp, but it differs from the latter by the presence of distinctly barbed notogastral setae la and lm and sparsely barbed setae c 1, c 2, lp, h 3 (versus these roughened, without barbs), shorter and thinner dorsal notogastral setae (versus longer and thinner), anterior median ventral tubercle (versus completely absent), and by distance between insertions of setae lm–lp (distinctly longer than that of la–lm and lp–h 3 versus little longer).

Additional known locations in U.S.A. (based on personal data of R.A. Norton)

New Hampshire, Belknap County, South Barnstead , from forest litter 17.IX.1965 (collected by R. M. Reeves) .

New York, Cortland County, Tully, Heiberg Memorial Forest, from litter in hardwood forest, VI.1959 (collected by R. Hartenstein). These specimens were studied by Hartenstein (1962) and misidentified as Metabelba montana (see Marshall et al. 1987, p. 352).

New York, Onondaga County, Cicero, Cicero Game Management Area , from forest litter, 14.IV.1970 (collected by D. Folts) .

New York, Onondaga County, Clark Reservation State Park, Glacier Lake basin, from deep forest humus on N-facing talus slope, under mixed hardwoods, Taxus , 02.XI.2016 (collected by R. A. Norton) .

New York: Warren County, Warrensburg, Pack Forest , from litter of red pine ( Pinus resinosa ) forest, 25.IV.1973 (collected by T. Finger) .

New York, Oneida County, McConnellsville, from litter in cherry ( Prunus serotina ) and white pine ( Pinus strobus ) forest, 20.XII.1973 (collected by D. Schultz).

Pennsylvania, Clarion County, Clarion , from Rhododendron litter, IV.1973 (collected by G. Edwards) .

Pennsylvania, Crawford County, Bousson National Laboratory , from mixed pine and hemlock forest litter, 3.II.1973 (collected by D.P. Schwert) .

Pennsylvania, Sullivan County, Hillsgrove , from mixed hardwood, hemlock forest, 13.V.1975 (collected by R. A. Norton) .

Vermont, Bennington County, Route 9, ca. 5 miles east of Bennington , mixed hardwood forest litter, 23.VII.1975 (collected by R. A. Norton) .

Vermont, Chittendon County, Route. 100, ca, 2 miles south of Stowe , white pine ( Pinus strobus ) forest litter, 29.VII.1975 (collected by R. A. Norton) .

Figures

FIGURE 7. Parabelbella pseudoinaequipes sp. nov., adult: A—dorsal view (legs not shown); B—ventral view (legs not shown); C—lateral view (gnathosoma and legs not shown). Scale bar 100 μm.

FIGURE 8. Parabelbella pseudoinaequipes sp. nov., adult: A—leg I, right, antiaxial view; B—leg II, right, antiaxial view. Scale bar 50 μm.

FIGURE 9. Parabelbella pseudoinaequipes sp. nov., adult:A—leg III, left, antiaxial view; B—leg IV, left, antiaxial view. Scale bar 50 μm.

FIGURE 10. Parabelbella pseudoinaequipes sp. nov., adult, SEM micrographs: A—dorsal view; B—ventral view; C—lateral view; D—cerotegument on notogaster. Scale bar 100 μm (A–C), 5 μm (D).

FIGURE 11. Parabelbella pseudoinaequipes sp. nov., adult, microscope images: A—lateral view; B—interbothridial region, dorsal view; C—setae in anterior part of notogaster, dorsal view; D—anterior median ventrosejugal tubercle Ma, ventral view; E—posterior ventrosejugal tubercle Vp, ventral view; F—parastigmatic apophyses Sa and Sp and discidium, ventral view.

FIGURE 12. Parabelbella pseudoinaequipes sp. nov., adult, microscope images: A—dorsal notogastral setae, lateral view (topotype); B—some notogastral setae (specimen from New York, Tully).