Trichoribates sidorchukae, Behan-Pelletier & Ermilov, 2019

Behan-Pelletier, Valerie M. & Ermilov, Sergey G., 2019, Trichoribates sidorchukae sp. nov. (Acari, Oribatida, Ceratozetidae) from tropical montane Ecuador, with revised generic diagnosis, Zootaxa 4647 (1), pp. 348-361 : 351-358

Trichoribates sidorchukae sp. nov.

( Figs 1–6 )

Material examined

Holotype (female) and one paratype (female): Ecuador, Pichincha Province, above Tandapi, 2300 m a.s.l., sweep sample in montane rainforest, 8.II.1983 (collected by L. Masner & M. Sharkey) . Seven paratypes (females): Ecuador, Chirimachay Matadero River , drift net sample, 14.I.1977 (collected by P. Turcotte)

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Type deposition

The holotype and one paratype are deposited in the Canadian National Collection, Ottawa, Canada. Seven paratypes are deposited in the collection of the Tyumen State University Museum of Zoology, Tyumen, Russia. All are in ethanol with a drop of glycerol.

Diagnosis

Body size: 464–614 × 298–381. Rostrum broadly rounded or slightly conical. Lamellar cusp longer than half length of lamella, with strong outer tooth, medial tooth absent. Translamella short, thick. Tutorium broadly triangular distally. Rostral, lamellar and interlamellar setae long, setiform, barbed, in longest. Bothridial seta short, head globular to clavate, barbed. Stalk of bothridial seta and bothridium covered by anterior notogastral margin. Bothridium without medial scale. Lenticulus triangular, indistinct or not evident. Four pairs of rounded notogastral porose areas. Ten pairs of notogastral setae comparatively short, setiform, barbed. Epimeral setal formula: 3-1-2-2. Leg genua without triangular process. Seta l’ of femur III absent; tibiae and genua III and IV with slightly thickened seta l’. Porose areas weakly developed proximoventrally on tarsi and distoventrally on tibiae.

Description

Measurements. Body length: 597 (holotype), 464–614 (8 paratypes); notogastral width: 381 (holotype), 298–381 (8 paratypes).

Integument ( Figs 3D , 6A, 6B ). Body color yellowish to brown. Dorsal and ventral of body with indistinct short stria; podosomal region slightly microgranulate. Dorsal side of tutorium striate.

Prodorsum ( Figs 1 , 3A, 3C , 4A , 6C, 6D ). Rostrum mostly broadly rounded, rarely slightly conical (in some paratypes). Anterior part of prodorsum with rostral bulge. Lamella (excluding cusp) distinctly shorter than half of prodorsum. Lamellar cusp longer than lamella (excluding cusp), with strong outer tooth, medial tooth absent. Trans- lamella short, thick. Tutorium long, broadly triangular distally. Rostral (77–102), lamellar (73–98) and interlamellar (135–200) setae setiform, barbed; basal part of rostral seta covered by tutorium. Bothridial seta (36–45) barbed, with short stalk and short, globular to clavate head. Bothridial stalk and bothridium covered by anterior notogastral margin. Bothridium without medial scale. Exobothridial seta (12–20) setiform, barbed. Dorsosejugal porose area present, diffuse. Dorsophragmata located close to each other, slightly separated.

Notogaster ( Figs 1 , 2 , 3A, 3B , 4B ). Anterior margin nearly straight. Lenticulus triangular, indistinct or not evident. Pteromorph broadly rounded laterally. Four pairs of rounded porose areas (all 12–20). Ten pairs of notogastral setae comparatively short (16–20), setiform, barbed. Lyrifissures (ia, im, ip, ih and ips) and opisthonotal gland opening distinct.

Gnathosoma ( Figs 4 C–4E). Subcapitulum longer than wide (139–151 × 90–102). Subcapitular setae setiform, h (24–28) and m (32–36) distinctly barbed, a (20–24) slightly barbed. Adoral setae (12) barbed. Palps (86–90) with setation 0-2-1-3-9(+ω). Postpalpal seta (8) spiniform. Axillary saccule distinct (4). Chelicera (139–151) with two barbed setae, cha (45–53) longer than chb (32–36).

Lateral podosomal and epimeral regions ( Figs 2 , 3A , 4A ). Genal tooth elongate triangular. Humeral porose areas Am and Ah indistinct, diffuse; Al absent. Custodium short, strong. Discidium triangular. Circumpedal carina long, directed to custodium. Horizontal folds present in integument between and dorsal of acetabula II and III. Epimeral setal formula: 3–1–2–2. Epimeral setae setiform, barbed; 1a, 2a and 3a (12–16) shorter than others (20–28).

Anogenital region ( Figs 2 , 3A, 3B, 3D, 3E , 4B ). Six pairs of genital (20–28), one pair of aggenital (16–24), two pairs of anal (16–24) and three pairs of adanal (16–24) setae, setiform, barbed. Adanal lyrifissure located close and parallel to anal plate. Preanal organ goblet-like. Ovipositor elongated (200–221 × 49–61), blades (90–98) shorter than length of distal section (beyond middle fold; 110–123). Each of three blades with four setae, ψ 1 ≈ τ 1 (41–49) setiform, longer than thorn-like ψ 2 ≈ τ a ≈ τ b ≈ τ c (16–20), all smooth. Six coronal setae (16) thorn-like, smooth.

Legs ( Figs 5 A–5D). Porose areas weakly developed proximoventrally on tarsi and distoventrally on tibiae. Genua without triangular process. Formula of leg setation and solenidia: I (1-5-3-4-20) [1-2-2], II (1-5-3-4-15) [1- 1-2], III (2-2-1-3-15) [1-1-0], IV (1-2-2-3-12) [0-1-0]; homology of setae and solenidia as indicated in Table 1 . Seta l’ of femur III absent. Tibiae and genua III and IV with slightly thickened seta l’.

Etymology

This species is named in honour of our esteemed colleague, friend and collaborator, Dr. Ekaterina (Katya) Sidorchuk (Paleontological Institute, Russian Academy of Sciences, Moscow, Russia). Katya introduced us to the detail of the world of acarine diversity in amber inclusions. She gave so much joy in her interactions with us. We will miss her.

Differential diagnosis

Trichoribates sidorchukae sp. nov. differs from other species of Trichoribates by the following combination of morphological traits: lamellar cusps longer than lamella (without cusp), with strong outer tooth and medial tooth absent; translamella short, thick; tutorium triangular; rostral, lamellar and interlamellar setae long, with in longest; bothridial seta short, with globular, barbed head; four pairs of rounded notogastral porose areas; ten pairs of notogastral setae comparatively short, setiform, barbed; epimeral setal formula: 3-1-2-2; leg genua without triangular process, seta l’ of femur III absent; porose areas weakly developed distoventrally on tibiae and proximoventrally on tarsi.

Trichoribates sidorchukae sp. nov. is morphologically most similar to Trichoribates myrica Gjelstrup & Solhøy, 1994 described from Iceland, and known also from Germany ( Weigmann 2006). Both species share the long lamellar cusp with pointed lateral dens and absence of medial dens, tutorium with broad pointed cusp overlaying base of rostral seta, short bothridial seta with club-shaped head, and bothridium without medial scale. They differ in the following: rostrum with medial ridges in T. myrica (absent in T. sidorchukae sp. nov.); bothridial stalk not covered by anterior notogastral margin in T. myrica (covered in T. sidorchukae sp. nov.); genu I with anteroventral process in T. myrica (absent in T. sidorchukae sp. nov.); notogastral setae medium long in T. myrica such that distance h 1 –h 1 less than length h 1 (notogastral setae short, such that distance h 1 –h 1 longer than length h 1 in T. sidorchukae sp. nov.). Weigmann & Norton (2009) considered Oribata setosa as illustrated by Michael (1888, his Plate VII, figs 3 – 12) possibly represented T. myrica . However, the adult illustrated has longer bothridial setae than those described for T. myrica by Gjelstrup & Solhøy (1994).

The new species is also similar to Trichoribates oblongarea Gjelstrup & Solhøy, 1994 described from Iceland. Both species share lamellar cusps with pointed lateral dens and absence of medial dens, tutorium with broad pointed cusp overlaying base of rostral seta, short bothridial seta with club-shaped head and bothridium without medial scale. They differ in the following: 11 pairs of notogastral setae in T. oblongarea (10 pairs in T. sidorchukae sp. nov.); porose area Aa oblong and narrow in T. oblongarea (round in T. sidorchukae sp. nov.); bothridium with medial, pointed scale in T. oblongarea (absent in T. sidorchukae sp. nov.); notogastral setae medium long in T. oblongarea such that distance h 1 –h 1 less than length h 1 (notogastral setae short such that distance h 1 –h 1 longer than length h 1 in T. sidorchukae sp. nov.). We were unable to compare these species described by Gjelstrup and Solhøy (1994) more closely as the types are mislaid (Thomas J. Simonsen, Entomology, Natural History Museum Aarhus, Denmark, pers. comm.).

Trichoribates sidorchukae sp. nov. also shares the pointed lateral dens of the lamellar cusp and absence of medial dens with Trichoribates oxypterus ( Berlese, 1910) . This is based on the illustration of the prodorsum of this Berlese species by Mahunka & Mahunka-Papp (1995). Bayartogtokh & Schatz (2008) noted that T. oxypterus sensu Berlese is not the same as T. oxypterus sensu Schweizer (1956) , and thus the synonymy of T. oxypterus with ( Kramer, 1897) by Subías (2004) cannot be supported.

Trichoribates sidorchukae sp. nov. shares the presence of porose areas proximoventrally on tarsi I – IV with T. striatus ( Behan-Pelletier 1986) , and Trichoribates novus Sellnick, 1928 ( Bayartogtokh et al. 2002) and proximoventrally on tarsi II and III with Trichoribates zingerlei Bayartogtokh & Schatz, 2008 (their Figs 2C , 3A ). Trichoribates sidorchukae sp. nov. is the only Trichoribates described with porose areas distoventrally on tibiae I – IV.As both leg setation and presence or absence of porose areas have not been studied in detail in many species of Trichoribates , these character states may be more widespread.

Trichoribates from the Neotropics

There are only two records of Trichoribates from the Neotropics, but none previously from Ecuador ( Illig et al. 2007). Schatz (2006) recorded the presence of an unnamed species from high elevation (2900–3500m) in Costa Rica and Panama. Hammer (1961) described Trichoribates hammerae Subías, 2010 (= Jugatala montana Hammer, 1961 , “nom. praeoc.” for Irk 1939) from moss and Ranunculus sp. near Huaraz, Peru, at an elevation of 4800m. Pérez-Íñigo & Pérez-Íñigo 1993 described Trichoribates serratus C. & C., jr. Pérez-Íñigo, 1993 from the branches of Araucaria from Brazil. As with T. hammerae , T. sidorchukae sp. nov. is known from high elevation montane.

Figures

FIGURE 1. Trichoribates sidorchukae sp. nov., adult: dorsal view (legs not shown). Scale bar 100 μm.

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

FIGURE 3. Trichoribates sidorchukae sp. nov., adult:A—anterior part of body, lateral view (legs and palp not shown); B—posterior part of body, lateral view; C—bothridial seta; D—right genital plate and part of epimeral region; E—ovipositor (inverted dorsal view, one ventral lobe hidden). Scale bar 100 μm (A, B), 20 μm (C–E).

FIGURE 4. Trichoribates sidorchukae sp. nov., adult: A—tutorium and genal tooth, lateral view; B—posterior view; C—subcapitulum, ventral view; D—palp, left, paraxial view; E—chelicera, left, paraxial view. Scale bar 20 μm (A, C–E), 100 μm (B).

FIGURE 5. Trichoribates sidorchukae sp. nov., adult:A—leg I, left, paraxial view; B—leg II, except tarsus, left, antiaxial view; C—leg III, except tarsus, left, antiaxial view; D—leg IV, right, antiaxial view. Scale bar 20 μm.

FIGURE 6. Trichoribates sidorchukae sp. nov., adult, light microscope images, DIC illumination: A—striate integument of notogaster; B—striate integument of anogenital region; C—lamellar cusp; D—tutorial cusp and anterior margin of tutorium (indicated by arrows), lateral view.

Tables

TABLE 1. Leg setation and solenidia of adult Trichoribates sidorchukae sp. nov.

Leg	Tr	Fe	Ge	Ti	Ta
I	v’	d, (l), bv”, v”	(l), v’, σ	(l), (v), φ1, φ2	(ft), (tc), (it), (p), (u), (a), s, (pv), v’, (pl), l”, ɛ, ω1, ω2
II	v’	d, (l), bv”, v”	(l), v’, σ	(l), (v), φ	(ft), (tc), (it), (p), (u), (a), s, (pv), ω1, ω2
III	l’, v’	d, ev’	l’, σ	l’, (v), φ	(ft), (tc), (it), (p), (u), (a), s, (pv)
IV	v’	d, ev’	d, l’	l’, (v), φ	ft”, (tc), (p), (u), (a), s, (pv)

Note: Roman letters refer to normal setae, Greek letters to solenidia (except ɛ = famulus). Single prime (’) marks setae on anterior and double prime (”) setae on posterior side of the given leg segment. Parentheses refer to a pair of setae.