Spatiodamaeus kalugaensis, Ermilov & Miko & Kolesnikov & Salavatulin, 2023

Ermilov, Sergey G., Miko, Ladislav, Kolesnikov, Vasiliy B. & Salavatulin, Vladimir M., 2023, Ontogenetic instars of the oribatid mite Spatiodamaeus kalugaensis sp. nov. (Acari, Oribatida, Damaeidae) from Russia, Zootaxa 5324 (1), pp. 49-65 : 50-60

Spatiodamaeus kalugaensis sp. nov.

( Figs 1–9 )

Diagnosis. Adult. — Body length: 720–870. Cerotegument filamentous.Exuvial scalps usually present on notogaster. Propodolateral apophysis absent. Three pairs of simple prodorsobasal tubercles (Da, Ba, Bp); Dp slightly developed or indistinct, forming transverse ridge. Rostral and lamellar setae setiform, barbed; interlamellar seta rod-like; barbed; bothridial seta rod-like, blunted, barbed in mediodistal part. Spina adnata of medium length, thorn-like. Notogastral setae of c -, l - and h -series medium-sized, thorn-like; c 1, c 2, la, lm, lp of dark color, thick, barbed; h 1, h 2, h 3 comparatively lighter and thinner; p 1, p 2, p 3 long, setiform, barbed. Ventral enantiophyses E2 and V present, M absent. Parastigmatic tubercle Sa long, thorn-like, Sp tubercle-like, quadrangular to trapezoid. Epimeral setal formula: 3-4-3-4. Epimeral, genital and aggenital setae setiform, barbed; anal and adanal setae setiform, shortly ciliate. Discidium narrowly triangular. Legs I and IV longer than body length; leg IV longest; formulas of leg segments (I–IV): femur 7-6-4-4; genu and tibia 4-4-3-3; tarsus 21-18-18-15; famulus emergent; seta v 2 ’ present on all tarsi. Juvenile instars.—Cerotegument mostly bacilliform and filamentous. Bothridial seta rod-like, blunt-ended, barbed in mediodistal part. Gastronotic setae setiform or subflagellate, barbed; c 1, c 2, da, dm, dp, lp longest in larva; h 1 longest in nymphal instars. Dorsal setae with large sclerite at the base. Tritonymph with two pairs of setae on epimere II. Epimeral and anogenital setae setiform, barbed. Famulus sunken.

Desciption

Adult. Measurements. Body length: 870 (holotype, female), 720–870 (four female paratypes), 765 (one male paratype); notogastral width: 555 (holotype), 525–570 (four female paratypes), 525 (one male paratype).

Integument ( Figs 1A, B, D, F, G ). Color medium to dark brown in preserved mature adults. Cerotegument conspicuous, excrescences varying in length but mostly filamentous on body and legs; setae usually without cerotegument. Procuticle mostly smooth.

Prodorsum ( Figs1A ; 2A,B ; 4A, C, D ).Rostrum broadly rounded.Propodolateral apophysis absent.Prodorsobasal tubercle Da and postbothridial enantiophysis (Ba, Bp) well developed, subconical, distally rounded, similar in size; Dp slightly visible (sometimes not observed), fused medially, forming transverse ridge; laterosejugal enantiophysis absent. Rostral (101–112) and lamellar (165–176) setae setiform, barbed; le thicker than ro; interlamellar seta (120–124) rod-like, erect, barbed; bothridial seta (150–161) rod-like, blunt-ended, barbed in mediodistal part; exobothridial seta (64–71) setiform, barbed; alveolar vestige of second exobothridial seta present posterior to seta ex. Mutual distance of bothridial openings slightly greater than that of tubercles Ba.

Notogaster ( Figs 1A ; 2A, B ; 4A, C, E ). Usually with full stack of juvenile exuvial scalps, sometimes with other adherent structures, particularly eggs or eggshells and fecal pellets, but without compacted organic debris. Nearly circular in outline; uniformly curved, hemispherical with maximum height in middle. Spina adnata (75–82) shorter than a mutual distance of pair, thorn-like, directed anterolaterad, reaching level of tubercles Da and Ba. Dorsal notogastral setae c 1 (127–131), c 2 (94–105), la, lm, lp (79–90) of dark color, thorn-like, thick, barbed; h 1, h 2, h 3 (116–127) comparatively lighter and thinner than the previous, smooth; posterior setae (p -series; 127–142) setiform, barbed. Opisthonotal gland opening and all notogastral lyrifissures distinct in transmitted light.

Gnathosoma ( Figs 2C–E ). Subcapitulum size: 184–195 × 135–150; subcapitular setae (a: 37–45; m, h: 71–82) setiform, barbed; both adoral seta (19–22) setiform, smooth. Palp (length: 142–150) with the typical formula: 0- 2-1-3-9(+ω); ω bacilliform, appressed to surface; postpalpal seta (6–7) spiniform, roughened. Chelicera (length: 184–195) with two setiform setae; cha (53–56) barbed, chb (45–49) unilaterally ciliate in mediodistal part; paraxial side of chelicera with several microteeth.

Epimeral and lateral podosomal regions ( Figs 1B ; 2B ; 4B, C, F, G ). Tectum of podocephalic fossa normally developed, without lateral tooth-like projection. Medial coxisternal pit present on epimere I, shallow, with vaguely defined margins. Ventrolateral ridge distinct. Epimeral enantiophysis E2 and ventrosejugal enantiophysis V well developed; mediosejugal enantiophysis M absent. Parastigmatic tubercles dimorphic: Sa long, thorn-like; Sp tubercle-like, quadrangular to trapezoid, distally truncated, directed nearly perpendicular to Sa. Epimeral setal formula: 3-4-3-4; all setae (1a, 2a, 3a: 45–52; others: 90–105) setiform, barbed; 3c clearly shifted medially from tubercle Sp and acetabulum III; epimere II of one specimen from Voronezh District included three setae on one side versus five setae on the other side. Discidium narrowly triangular.

Anogenital region ( Figs 1B ; 2B ; 4B, C, G ). Genital (64–79) and aggenital (90–105) setae setiform, barbed; anal and adanal setae (64–79) setiform, shortly ciliate. Adanal lyrifissure oriented diagonally.

Legs ( Figs 3A–D ; 4A–C ). Legs II and III shorter than body length, legs I and IV longer than body length, leg IV longest; approximate length of leg segments shown in Table 1 . Claw of each tarsus smooth. Porose area on femora I-IV and on trochanters III and IV distinctly visible. Formulas of leg setation and solenidia: I (1-7-4-4-21) [1-2-2], II (1-6-4-4-18) [1-1-2], III (2-4-3-3-18) [1-1-0], IV (1-4-3-3-15) [0-1-0]; homology of setae and solenidia indicated in Table 2 . Famulus of tarsus I emergent, setiform, inserted between solenidia ω 1 and ω 2; seta v 2 ’ present on all tarsi; solenidion on genua I-III shorter than coupled setae d.

Juvenile instars. Measurements. Total length of larva: 240–345 (n=3), protonymph: 360, 465 (n=2), deutonymph: 524–630 (n=7), tritonymph: 675, 720 (n=2). Total width of larva: 135–165 (n=3), protonymph: 180, 225 (n=2), deutonymph: 285–360 (n=7), tritonymph: 390, 450 (n=2).

Integument ( Figs 9A–D ). Cerotegument represented by thick layer consisting mostly short, bacilliform components, partially tubercles and long, filamentous parts. Surface of body colorless to light brownish (from larva to tritonymph). Cuticle slightly folded except prodorsum and centrodorsal region in nymphal instars. All body setae usually without cerotegument.

Prodorsum ( Figs 5A, C ; 8A ; 9A, B, D ). Relatively short, about 2/3 and 1/2 length of gastronotic region in larva and nymphal instars, respectively. Rostrum broadly rounded. Rostral (LA: 37–41; PN: 49–572; DN: 64–67; TN: 90–105) and lamellar (LA: 56–60: PN: 86–90; DN: 120–127; TN: 135–142) setae setiform, barbed; exobothridial (LA: 41–49; PN: 56–60; DN: 67–71; TN: 71–82) and larval interlamellar (45–49) setae setiform, nearly straight, barbed, ex directed anterolaterad, in directed posterolaterad; nymphal interlamellar seta (PN: 22–26; DN: 30–34; TN: 45–49) bacilliform, smooth except for terminal denticles; bothridial seta (LA: 90–105: PN: 112–120; DN: 120–127; TN: 131–139) rod-like, blunt-ended, barbed in mediodistal part.

Gastronotic region ( Figs 5A, C ; 8A ; 9A, B, D ). Posteriorly rather rounded, with large protruding pygidial sclerite. With exuvial scalps from the pervious instars; each scalp reticulate, with nine pairs of setae. Twelve pairs of dark color, setiform or subflagellate, barbed gastronotic setae inserted on large or small tubercles; sometimes setae with additional long, light, flagellate tip. True length of dorsal setae in nymphal instars often unknown, because their tips always broken, however, the length ratio can be assumed based on setae residues: LA: c 1, c 2, da, dm, dp, lp> h 1> c 3, la, lm> h 2> h 3; PN, DN, TN: h 1> c 1, c 2, la, lm, lp, h 3> h 2> c 3, p 1> p 2, p 3. Large sclerite located at the base of c 1, c 2, la, lm, lp, h 1, h 2 in nymphal instars. Cornicle thorn-like, slightly curved in mediodistal part, located between insertions of setae h 2 or h 3. Opisthonotal gland opening and all cupules and distinct.

Gnathosoma ( Figs 5D–F ). Subcapitulum size: LA: 64–67 × 86–90; PN: 82–86 × 94–97; DN: 105–112 × 105– 112; TN: 124 × 124); all subcapitular setae (LA: a, m: 19–22; h: 13–15; PN: a, m: 30; h: 22; DN: a, m: 34–37; h: 30–34; TN: a, m: 37–41; h: 30–34) setiform barbed; adoral seta (LA: 4; PN: 7; DN: 9; TN: 12) setiform, smooth. Palp (LA: 64–67; PN: 79–82; DN: 94–97; TN: 110–112) with setation 0-1-1-3-9(+ω) in larva and 0-2-1-3-9(+ω) in nymphal instars; solenidion bacilliform, appressed to surface; postpalpal seta (LA and PN: 4; DN and TN: 6–7) spiniform, roughened. Chelicera (LA: 67–71; PN: 90–94; DN: 118–123; TN: 135–142) with two setiform setae; cha (LA: 19–22; PN: 22; DN: 30–34; TN: 41–45) barbed, chb (LA: 15–17; PN: 19; DN: 26–30; TN: 34–37) unilaterally ciliate in mediodistal part.

Epimeral region ( Figs 5B, C ; 7A, B ; 8B ; 9C ). Setal formulas for epimeres: larvae 3-1-2 (1c as typical scale covering Claparède’s organ); protonymph: 3-1-2-1; deutonymph: 3-1-2-2, tritonymph: 3-2-3-3; all setae (LA: 1b, 3b: 15–19; others: 11–15; PN: 1b, 1c, 3b: 22–30; others: 19–22; DN: 1b, 1c, 3b, 4a: 27–34; others: 22–24; TN: 1b, 2b, 3b, 3c, 4a, 4b: 41–45; others: 26–30) setiform, barbed.

Anogenital region ( Figs 5B, C ; 7A, B ; 8B ; 9C ). Ontogeny of genital (PN: 22; DN: 22–26; TN: 28–30), aggenital (DN: 22–26; TN: 28–30), adanal (DN: 34; TN: 41–52), and anal (TN: 28–30) setal formulas, proto- to tritonymphs: 1- 3-5, 0-1-1, 0-3-3, 0-0-2, respectively; all setae setiform, barbed. Adanal cupule distinct; anal cupule not observed.

Legs ( Figs 6A–C ; 9A–9 ). Claw of each leg smooth. Porose area on all femora distinctly visible, located ventrodistally. Formulas of leg setation and solenidia: larva I (0-2-3-4-16) [1-1-1], II (0-2-3-3-13) [1-1-1], III (0- 2-2-3-13) [1-1-0]; protonymph I (1-3-3-4-16) [1-1-2], II (1-3-3-4-13) [1-1-1], III (1-3-3-3-13) [1-1-0], IV (0-0-0- 0-7) [0-0-0]; deutonymph I (1-4-4-5-16) [1-2-2], II (1-4-4-5-13) [1-1-2], III (2-3-3-4-13) [1-1-0], IV (1-3-3-3-12) [0-1-0]; tritonymph I (1-5-4-5-19) [1-2-2], II (1-4-4-5-16) [1-1-2], III (2-3-3-4-16) [1-1-0], IV (1-3-3-4-13) [0-1-0]; homologies of setae and solenidia indicated in Table 2 . Famulus sunken in cup, non-emergent, with distinct internal ‘root’.

Material examined. Holotype (female), five paratypes (four females, one male) and 14 juvenile instars (three larvae, two protonymphs, seven deutonymphs, two tritonymphs): European part of Russia, Kaluga District, Ulyanovsk region, near Kireykovo village, 53°38'8"N, 35°52'19"E, Kaluzhskiye Zaseki Nature Reserve , southern part, old-growth polydominant broadleaf forest (with dominance of Acer platanoides , Fraxinus excelsior , Quercus robur , Populus tremula , Tilia cordata , Ulmus glabra ), bark from crown of Acer platanoides at the height of 10 m, 01.10.2021 (leg. V.M. Salavatulin and A.A. Kudrin).

Additional (non-type) material. Six specimens (two males and four females): European part of Russia, Voronezh District, vicinities of the Aydarovo village, 51°54'N, 39°18'E, mixed forest (with dominance of Pinus silvestris , Populus tremula , Quercus robur ), soil-litter, 5.V.2018 (leg. V. B. Kolesnikov). Seven specimens (two males and five females); Russian Western Siberia, Tyumen District, Nizhnetavdinsky region, near Tangachi village, 57°21'31"N 66°02'50"E, mixed forest (with dominance of Betula sp. , Tilia cordata , Pinus sylvestris ), litter, 20.03.2021 (leg. V.M. Salavatulin).

Type deposition. The holotype, five paratypes and juvenile instars are deposited in the collection of the Tyumen State University Museum of Zoology, Tyumen, Russia. Additional (non-type) materials are in the personal collection of the first and third authors. All specimens are preserved in 70% solution of ethanol with a drop of glycerol.

Etymology. The species name refers to the place of origin of the type specimens, Kaluga District.

Differential diagnosis. The adult of Spatiodamaeus kalugaensis sp. nov. is morphologically similar to S. nortoni ( Bayartogtokh, 2004) comb. nov. from Mongolia in having neotrichy on epimere II (four pairs of setae). However, the new species differs from the latter by the presence (versus absence) of parastigmatic tubercle Sa, the form of parastigmatic tubercle Sp (quadrangular or trapezoid versus triangular) and notogastral setae c 1, c 2 (thorn-like versus slightly phylliform), and the barbulation of rostral, epimeral, anogenital, and notogastral setae of p -series (barbed versus smooth).

Figures

FIGURE 1. Spatiodamaeus kalugaensis sp. nov., adult: A—dorsal view (exuvial scalps and legs not shown); B—ventral view (gnathosoma and legs not shown). Scale bar 200 μm.

FIGURE 2. Spatiodamaeus kalugaensis sp. nov., adult: A—habitus, right lateral view (exuvial scalps not shown); B— right lateral view (exuvial scalps, gnathosoma and legs not shown); C—subcapitulum, ventral view; D—palp, right, antiaxial view; E—chelicera, left, paraxial view. Scale bars 200 μm (A, B), 50 μm (C–E).

FIGURE 3. Spatiodamaeus kalugaensis sp. nov., adult:A—leg I, right, antiaxial view; B—leg II, right, antiaxial view; C—leg III, left, antiaxial view; D—leg IV, left, antiaxial view. Scale bar 100 μm.

FIGURE 4. Spatiodamaeus kalugaensis sp. nov., adult, microscope images: A—dorsal view (exuvial scalps removed); B— ventral view; C—right lateral view (exuvial scalps removed); D—bothridium and some prodorsal setae, lateral view; E—scalps on notogaster; F—part of epimeral region, ventral view; G—part of epimeral and anogenital regions, ventral view. Magnification 200 (A–C, E), 1000 (D, F, G).

FIGURE 5. Spatiodamaeus kalugaensis sp. nov., larva: A—dorsal view (some notogastral setae broken; legs not shown); B—ventral view (some notogastral setae broken; gnathosoma and legs not shown); C— right lateral view (gnathosoma and legs not shown); D—subcapitulum, ventral view; E—palp, left, paraxial view; F—chelicera, left, paraxial view. Scale bars 100 μm (A–C), 20 μm (D, F), 10 μm (E).

FIGURE 6. Spatiodamaeus kalugaensis sp. nov., larva: A—leg I, right, antiaxial view; B—leg II, right, ventroantiaxial view; C—leg III, left, ventroantiaxial view. Scale bar 20 μm.

FIGURE 7. Spatiodamaeus kalugaensis sp. nov., nymphs: A—protonymph, ventral view (gnathosoma and legs not shown); B—deutonymph, ventral view (gnathosoma and legs not shown). Scale bars 100 μm.

FIGURE 8. Spatiodamaeus kalugaensis sp. nov., tritonymph: A—dorsal view (notogastral setae broken; exuvial scalps and legs not shown); B—ventral view (some notogastral setae broken; gnathosoma and legs not shown). Scale bar 100 μm.

FIGURE 9. Spatiodamaeus kalugaensis sp. nov., juvenile instars, microscope images:A—larva, dorsal view; B—deutonymph, dorsal view; C—deutonymph, ventral view; D—deutonymph, right lateral view. Magnification 200.