Scheloribates arsizonensis, Ermilov K & Rybalov K, 2023

Ermilov K, Sergey G. & Rybalov K, Leonid B., 2023, Ontogenetic instars of the oribatid mite Scheloribates arsizonensis n. sp. (Acari, Oribatida, Scheloribatidae) from Ethiopia, Acarologia 63 (1), pp. 122-135 : 124-133

publication ID	https://doi.org/ 10.24349/o0ta-ustm
persistent identifier	https://treatment.plazi.org/id/03DEF663-2F27-FFBF-FE45-1188FB391542
treatment provided by	Felipe
scientific name	Scheloribates arsizonensis
status	sp. nov.

Treatment

Scheloribates arsizonensis n. sp.

Zoobank: E8A5C7BD-7725-45C9-BD85-CA94E8C231C0

( Figures 2-7 View Figure 2 View Figure 3 View Figure 4 View Figure 5 View Figure 6 View Figure 7 )

Diagnosis — (adult) Body length: 675–735 × 450–510. Rostrum protruding, rounded. Prolamella absent; translamella represented by two short ridges. Rostral, lamellar and interlamellar setae long, setiform, barbed; ro shortest, in longest; exobothridial seta minute, simple; bothridial seta comparatively short, fusiform, pointed distally, barbed. Anterior notogastral margin convex medially. One pair of simple notogastral setae p (1) developed; other setae represented by alveoli. All epimeral setae setiform, slightly barbed. Circumpedal carina comparatively long. All anogenital setae setiform, slightly roughened. Marginal porose area complete. Ventroantiaxial part of trochanter III with tooth.

Description of adult — ( Figures 2 View Figure 2 a-d, 3a-g) Measurements – Body length: 705 (holotype: female), 675–735 (43 paratypes: 21 males and 22 females); body width: 465 (holotype), 450–510 (43 paratypes). No differences between males and females in body size.

Integument – Body color brown. Cuticle microsculpturing granulate (visible in dissected specimens under high magnification, ×1000); lateral part of body (between sublamella and pedotecta I, II) with granulate cerotegument.

Prodorsum ( Figures 2a, c View Figure 2 ) – Rostrum slightly protruding, narrowly rounded. Lamella about 1/2 length of prodorsum; prolamella absent; sublamella similar to lamella in length; sublamellar porose area rounded (6); translamella represented by two short ridges developed near lamellae. Rostral (76–94), lamellar (124–161) and interlamellar (180–221) setae setiform, barbed; exobothridial seta (9–11) setiform, smooth, often directed backwards; bothridial seta comparatively short (60–71), with fusiform, pointed distally, barbed head. Dorsosejugal porose area diffuse. Dorsophragma slightly elongate.

Notogaster ( Figures 2a, c, d View Figure 2 ) – Anterior notogastral margin slightly convex medially. One pair of notogastral setae (p 1: 15–22) developed, setiform, smooth; other setae represented by alveoli. Four pairs of sacculi drop-like. Opisthonotal gland opening and all lyrifissures distinct.

Gnathosoma ( Figures 3 View Figure 3 a-c) – Subcapitulum size: 142–150 × 116–130; subcapitular (a:

30–34; m: 28–30; h: 37–41) and adoral (19) setae setiform, barbed; m thinner than a and h.

Palp (length: 82–90) setation: 0-2-1-3-9 (+ω); solenidion bacilliform, not swollen distally; postpalpal seta (9) spiniform, roughened. Chelicera (length: 161–169) with two setiform, barbed setae (cha: 52–56; chb: 35–37).

Epimeral and lateral podosomal regions ( Figures 2b, c View Figure 2 ) – Epimeral formula: 3-1-3-3;

setae (1b, 3b: 37–41; 3c: 30–34; others: 19–26) setiform, slightly barbed. Pedotectum II rounded distally in ventral aspect. Discidium triangular, rounded distally. Circumpedal carina comparatively long, anteriorly directed to pedotectum II.

Anogenital region ( Figures 2 View Figure 2 b-d) – Genital g (1: 26–30; g 2 – g 4: 19–26), aggenital (19–26),

anal (19–26), and adanal (22–30) setae setiform, slightly roughened. Adanal lyrifissure distinct. Marginal porose area complete, narrowly band-like.

Legs ( Figures 3 View Figure 3 d-g) – Median claw distinctly thicker than lateral claws; all claws slightly barbed on dorsal side; lateral claws with small tooth distoventrally. Ventroantiaxial part of trochanter III with tooth; tibiae I, II with slightly developed tubercle proximoventrally. Dorsoparaxial porose area on femora I-IV and on trochanters III, IV, proximoventral porose area on tarsi I-IV, and distoventral porose area on tibiae I-IV well visible. Formulas of leg setation and solenidia: I (1-5-3-4-18) [1-2-2], II (1-5-2-4-15) [1-1-2], III (2-3-1-3-15) [1-1-0],

IV (1-2-2-3-12) [0-1-0]; homology of setae and solenidia indicated in Table 1 ; famulus short, slightly swollen distally, inserted posterior to solenidion 2 ω ; solenidion ω 1 on tarsus I and σ on genu III slightly bacilliform, ω 1 and ω 2 on tarsus II rod-like; other solenidia setiform.

Description of juvenile instars — ( Figures 4 View Figure 4 a-c, 5a, b, 6a-c,7a-h) Measurements – Total length of larva: 315–330 (n=5), protonymph: 390–420 (n=4), deutonymph: 465–510 (n=12), tritonymph: 555–645 (n=20); total width of larva: 135–150 (n=5), protonymph: 195–210

(n=4), deutonymph: 210–240 (n=12), tritonymph: 270–375 (n=20).

Integument ( Figures 4 View Figure 4 a-c, 5a, b, 6a-c, 7a-c) – Body colorless to light yellowish, legs, gastronotic sclerites, lateral parts of epimeres, and dorsal prodorsal sclerite light brown in deuto- and tritonymphs. Body surface densely porose (visible under high magnification in dissected specimens); additionally, gastronotum and anogenital region slightly folded; gastronotic region with two strong, long, longitudinal, dorsolateral folds.

Prodorsum ( Figures 4a, c View Figure 4 , 5a, b View Figure 5 , 6a, c View Figure 6 ) – Relatively short, about 1/2 (in larva) and 1/3 (in nymphal instars) length of gastronotic region. Rostrum rounded. Dorsal side of prodorsum with large sclerite bordered by lateral and postbothridial carinae. Rostral (LA: 34–37; PN: 41–45; DN: 53–57; TN: 64–67), lamellar (LA: 41–45; PN: 60–64; DN: 82–86; TN: 116–120) and interlamellar (LA: 60–64: PN: 97–105; DN: 131–139; TN: 172–176) setae setiform, barbed; exobothridial seta (LA: 1; PN: 2; DN, TN: 4) simple, smooth; bothridial seta (LA: 26–30; PN: 30–34; DN: 41–45; TN: 52–56) clavate, rounded distally, barbed.

Gastronotic region ( Figures 4 View Figure 4 a-c, 5a, b, 6a-c, 7a, b) – Posteriorly rather rounded. Nymphal instars with distinct ecdysial cleavage line (line of dehiscence). Larva with 12, nymphal instars with 15 pairs of setiform (except h 3 represented by alveolus in LA), slightly barbed setae; setae c 1, da, dm, dp thinner than others in larva; relative thickness of gastronotic setae in nymphal instars: c 3 ˃ c 2 ˃others; all setae with sclerite at the base, large sclerites at the base c of 2, la, lp, h 1

in larva, c 2, la, lp, h 2, h 3 in protonymph, c 2, la, lp, h 2, h 3, p 1 in deuto- and tritonymphs. Length of gastronotic setae: LA: c 3: 32–34, h 1, h 2: 26–30, others: 17–22; PN: c 3: 71–75, c 2: 22–26, others: 17–22; DN: c 3: 86–90, c 2: 26–30, others: 22–26; TN: c 3: 105–131, c 2: 26–37, lp, h 1,

h 2, h 3, p 1, p 2, p 3: 19–22, others: 26–30. Opisthonotal gland opening and all cupules distinct. Gnathosoma ( Figures 7c, d View Figure 7 ) – Subcapitulum size: LA: 57 × 49; PN: 67–71 × 60–64; DN: 86–90 × 79–82; TN: 105–109 × 97–101; length of subcapitular setae a, h: LA, PN: 15; DN: 17–19; TN: 22–26; length of subcapitular seta m: LA, PN: 11; DN: 13–15; TN: 17–19; length of adoral seta: LA, PN: 7; DN: 9–11; TN: 11–13; all subcapitular and adoral setae setiform, slightly barbed. Posterolateral part of subcapitular mentum with porose area. Palp length: LA: 34; PN: 45; DN: 52–56; TN: 64–67; palp formula: 0-2-1-3-9(+ω); solenidion connected with eupathidium in all instars; length of postpalpal seta: LA, PN: 4; DN, TN: 5–7. Chelicera length: LA: 56; PN: 75–82; DN: 94–97; TN: 112; length of seta cha: LA: 22; PN: 30; DN: 34–37; TN: 41–43; length of seta chb: LA: 15; PN: 19; DN: 20–22; TN: 26; both cheliceral setae setiform, barbed.

Epimeral and lateral podosomal regions ( Figures 4b, c View Figure 4 , 5a, b View Figure 5 , 6b, c View Figure 6 ) – Setal formulas for epimeres: larva: 3-1-2 (1c as typical scale covering Claparède’s organ); protonymph 3-1-2-1; deutonymph 3-1-2-2, tritonymph 3-1-3-3; length of setae: LA: 9–11; PN: 11–13; DN: 13–19;

TN: 19–22; all setae setiform, slightly roughened.

Anogenital region ( Figures 4b, c View Figure 4 , 5a, b View Figure 5 , 6b, c View Figure 6 , 7a, b View Figure 7 ) – Ontogeny of genital (PN: 11–13; DN: 13–19; TN: 17–19), aggenital (TN: 17–19), anal (TN: 17–19), and adanal (DN: 19–22; TN: 26)

setal formulas, proto- to tritonymph: 1-2-3, 0-0-1, 0-0-2, 0-2-2, respectively; all setae setiform, roughened; paraproctal setae absent. There is an unusual development of aggenital setae: they only appear in tritonymph instead in deutonymph. Adanal cupule distinct; anal cupule not observed.

Legs ( Figures 7 View Figure 7 e-h) – Claw of each leg dorsally slightly barbed. Femora I-IV with distoventral porose area. Formulas of leg setation and solenidia: larva I (0-2-2-3-16) [1-1-1],

II (0-2-2-2-13) [1-1-1], III (0-2-1-1-13) [1-1-0]; protonymph I (0-2-2-3-16) [1-1-2], II (0-2-

2-2-13) [1-1-1], III (1-2-1-1-13) [1-1-0], IV (0-0-0-0-7) [0-0-0]; deutonymph I (0-3-2-3-16)

[1-2-2], II (0-3-2-2-13) [1-1-2], III (1-2-1-1-13) [1-1-0], IV (0-2-1-1-12) [0-1-0]; tritonymph

I (1-4-2[or 3]-4-18) [1-2-2], II (1-4-2-3-15) [1-1-2], III (1-2-1-3-15) [1-1-0], IV (0-2-2-2-12)

[0-1-0]; homologies of setae and solenidia indicated in Table 1.

Material examined — Holotype (female), 43 paratypes (21 males and 22 females) and 41 juvenile instars (five larvae, four protonymphs, 12 deutonymphs, 20 tritonymphs): Ethiopia, Oromia Region, Arsi Zone, Arsi Mountains National Park , 07º17′49′′N, 039º23′40′′E, 3847 GoogleMaps

m a.s.l., litter and green moss Rhytidiadelphus triquetrus under mixed plants ( Erica arborea , Helichrysum spp. , Lobelia rhynchopetalum [giant lobelia], Alchemilla pedata , Haplocarpha rueppelii ) ( Fig. 1 View Figure 1 ), 03.12.2021 (L.B. Rybalov).

Type deposition — The holotype and two paratypes are deposited in the collection of the Senckenberg Museum of Natural History, Görlitz, Germany ; 41 paratypes and juvenile instars are deposited in the collection of the Tyumen State University Museum of Zoology, Tyumen, Russia. All specimens are preserved in 70% solution of ethanol with a drop of glycerol.

Etymology — The species name arsizonensis refers to the Arsi Zone, where the new species was collected.

Remarks — Although, Scheloribates is a large genus (210 species and 19 subspecies) and contains many similar species, adults of S. arsizonensis n. sp. can be distinctly distinguished from other representatives of the genus by the combination of morphological traits, e.g.: 1) body large: 675–735; 2) distinct sculpturing and ornamentation absent; 3) rostrum protruding, rounded; 4) prolamella absent; 5) translamella present, represented by two short ridges; 6) rostral, lamellar and interlamellar setae long, setiform, barbed, in ˃ le ˃ ro ; 7) bothridial seta comparatively short, fusiform, pointed distally, barbed; 8) anterior notogastral margin convex medially; 9) one pair of notogastral setae (p 1) developed, others represented by alveoli. The new species is morphologically most similar to Scheloribates praestantissimus praestantissimus ( Berlese, 1916) from Somalia (see Berlese 1916 ; Mahunka and Mahunka-Papp 1995) in having large body size, protruding, rounded rostrum, long rostral, lamellar and interlamellar setae (with relative length: in˃le˃ro), interrupted medially translamella, and the comparatively short bothridial seta, but differs from the later in having fusiform, pointed distally (versus clavate, rounded distally) bothridial seta, the absence (versus presence) of prolamella, and the presence (versus represented alveoli) of well-developed notogastral setae p 1.