Tuckerella weiterschani Sidorchuk & Khaustov 2018, n. sp.
Creators: name: Sidorchuk, Ekaterina A.
name: Khaustov, Alexander A.
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Prostigmata
Tuckerellidae
Tuckerella
Tuckerella weiterschani

description: Tuckerella weiterschani n. sp. (Figs 1–4)
Zoobank: AB714EE7-5602-4792-A9A0-B42618B1E983
Description — Tritonymph or adult, gender unknown. Length of idiosoma – 275, width – 155, height – 55; body length including gnathosoma – 310.
Gnathosoma (Figs 1, 2, 4) — Only right palp clearly visible. Palpgenu dorsally with seta d, reaching just beyond tip of tibia. Palptibia with large, hooked tibial claw and three setae: d, slightly longer than palpgenu; short l”, reaching to tip of tibial claw; medium-sized l’, about as long as palptibia+tibial claw. Palptarsus completely covered by tibial claw in dorsal view, and elongate, roughly necktie-shaped as visible in lateral view, 14 long, phaneres not visible. Subcapitulum long and narrow, with alveolus of seta m visible basally and one pair of small peg-like adoral setae visible apically (Fig. 2, arrow). Peritremes prominent and emergent (Figs 1H, 4A). Stylophore and cheliceral stylets not visible.
Idiosomal dorsum (Figs 1, 3, 4A) — Visible ornamentation reticulate (Fig. 1 D–F). Prodorsum with 4 pairs of setae (vertical v 1, v 2, scapular sc 1, sc 2). Setae v 2, sc 1 and sc 2 fan-like (Figs 1D, 4A); setae v 1 broadly lanceolate, with tapered tip (Fig. 1H). Two pairs of eyes located anterolaterally to bases of setae sc 1 (Figs 1F, 4A, oc); posterior eye distinctly larger than anterior. Hysterosoma with 7 setae in C-row, 6 in D-row, 3 in E-row, 2 in F-row, 8 in H-row. All setae in rows C–F broadly obovate to orbicular. Setae c 1 – c 3 and d 1 – d 3 of medium size (12x20), subequal. Setae e 1 and e 2 slightly smaller than c 1 – c 3 and d 1 – d 3. Setae f 1 and f 2 (8x14) distinctly smaller than e 1 and e 2; f 2 situated anterolaterally to bases of f 1. Setae c 4 (20x30) distinctly larger than c 1 – c 3; c 5 (20x40) more elongate and narrow than c 4; setae c 6 and
c 7 similar to c 5, but with stronger tapered tips, especially well visible on left side of body (Figs 1D, 3). Setae d 4 – d 6 and e 3 similar in shape to c 4 – c 7, but clearly larger (d 6 30x60). Distinct apophyses of h -series setae situated close to each other in one transverse line. Setae h 1 short, narrowly lanceolate, barbed, 30 long (Fig. 1G), much shorter than filiform and weakly barbed setae h 2 – h 8,. Setae h 2 – h 8 longer than body h (2 440) and directed dorsad and anteriad (Fig 1A, C, G, J). Only shield margins visible are anterior margins of dorsal shields C and D (Figs 1A, 3).
Idiosomal venter (Fig. 1B) — Somewhat collapsed, mostly obscured by legs. Cuticle lightly striate, setation not discernible. As far as visible, typical for females of Recent Tuckerella species (see for example Fig. 2 in Beard and Walter 2005). Genital and anal openings discernible, but no setae visible with certainty.
Legs (Figs 1B, J; 4) — Leg I (Fig. 4A, A’). Femur with 3 large, fan-like dorsal and lateral setae (d, l’, l”), and 2 small, setiform ventral setae visible (probably ventral v” and v 1 ”). Genu with 5 large, fan-like dorsal and lateral setae d, (l’, l 1 ’, l”, l 1 ”) and one visible setiform seta
v”. Tibia with large, fan-like setae l”, l 1 ”, l’; and more narrow d; solenidion φ baculiform, situated on short protuberance; single visible seta v” small, setiform. Tarsus with two claws and empodium with tenent hairs (Figs 1A, 4A, A’); two solenidia present, 1 ωabout 1.5 times longer than ω 2; unguinal setae (u) poorly visible, only on left leg, modified, comb-like; other setae on tubercles: abaxial members (”) of fastigial (ft) and primilateral (pl) pairs long, distinctly longer than tarsus, their adaxial members ft’ and pl’ about half as long; pl’ weakly barbed; tectal (tc) smooth, tapered; proral p” blunt, thick, probably eupathidial, possible alveolus of p’ visible on right leg; simple primiventral seta pv visible on left tarsus; on right tarsus, alveolus in position l 1 ” visible and what may be seta l 1 ” discernible. Leg II (Fig. 4B) setation partly visible, tip of tarsus and trochanter hidden in deformed venter. Femur with 3 fan-like d – and (l) – and one poorly visible simple seta, possibly basiventral bv”. Genu with 4 fan-like setae (d, (l), l 1 ’), tibia with 3 fan-like setae – d, (l) – visible. Tarsus with one blunt phanere on prominent tubercle (probably solenidion ω) and 7 simple setae or their alveoli visible: pv’, pairs (p) and (tc) on low tubercles, seta pl” and possible alveolus of ft”. Legs III and IV (Fig. 4C, D, D’) visible almost entirely, with paired claws, paired empodia and at least 4 pairs of tenent hairs each. Setation: leg III trochanter with single thick, heavily barbed seta l’ visible, femur with 2 setae: simple euventral ev’ and short, narrow, barbed d; genu with single short, narrow, barbed seta d visible, tibia with 3 setae: short, narrow, barbed d, fan-like l’, simple v’; tarsus with two setae and three alveoli visible, setal pair p () and solenidion apparently absent. Leg IV trochanter and femur without visible setae; genu with setiform v’ and short, narrow, barbed d, tibia with single short, narrow, barbed seta d visible. Tarsus with 7 setae: pairs (ft), (tc) and (u) visible dorsally (in ventral aspect of mite, Fig. 4 D’), seta pv ’ – in lateral aspect (Fig. 4D). Observed leg setation formulas: leg I:?-5-6-5(1)-12(2); leg II:?-4-4-3-7(1); leg III: 1-2-1-3-5; leg IV:?-?-2-1-7.
Holotype and type repository — Originally from private collection of Thomas Weiterschan, coll. # TW 1288, housed in the Geological-Paleontological Museum and University Hamburg (GPIH), collection number GPIH 4598. The holotype is the only inclusion in a rectangular light yellow amber piece measuring 1x0.7x 0.7 mm, polished on six sides, stored in plastic O-ring-capped vial with water and preservative Thymol (Fig. 1A).
Type locality, occurrence and geological age — Type locality is Baltic Sea Coast, amber in Blue Earth fossil beds, dated late Eocene. Only known from the type specimen and locality.
Etymology — The new species is named in honor of Thomas Weiterschan, who discovered the specimen, promoted its study and assured its holotype deposition in a public repository.
Remark — The holotype and only known specimen of T. weiterschani has emergent peritremata, leg I tarsal setae l 1 ” and leg I genual and tibial setae l 1 () present. These features suggest that the specimen is at least tritonymphal (Servin and Otero 1989, Beard and Walter 2005). In the presence of the tapered setae v 1 and lateral idiosomal setae and in the absence of clear view on the genital area, however, we cannot distinguish between an adult and a tritonymphal stage. Emergent peritremes in immature tuckerellid mites, not mentioned in the literature to our best knowledge, do occur at least in four Recent species starting from the deutonymphal stage (J. Beard, pers. comm.), and are thus inconclusive. The Diagnosis below is hence preliminary, and only uses those characters known to be relatively stable through the last two stages of the tuckerellid ontogeny.
Differential diagnosis — By the presence of seven pairs of subequal filiform setae h 2 – h 8 the new species is similar to five Recent species: T. coleogynis Jorgensen, 1967, T. elegans Rossi de Simons, 1972, T. eloisae Servin and Otero, 1989, T. hypoterra McDaniel and Morihara in McDaniel et al. 1975 and T. spechtae Womersley, 1957. The new species differs from T. spechtae and T. hypoterra by the relative positions of setal pairs f 1 and f 2, f 1 being inserted clearly posterior to f 2 in T. weiterschani, as opposed to slightly anterior in these two species; in addition, T. spechtae has setae h 6 shorter than the other flagellate setae. From T. eloisae the new species differs by its much smaller size (total body length – including gnathosoma – 310 in T. weiterschani vs. 480 in tritonymph, 473 – 566 in adults of T. eloisae). T. elegans, only slightly larger than T. weiterschani (adult idiosomal length 342 – 370 in T. elegans vs. 275 in T. weiterschani), and T. coleogynis differs from the new species by its setae v 1 having a smooth edge and uneven reticulation vs. these setae widely lancetiform, with tapered tips in T. weiterschani (the validity of this character is only certain if T. weiterchani holotype is an adult female), and having setae h 2 – h 8 as long as body, vs. at least 1.5 times body length in T. weiterschani. T. coleogynis, whose size is unknown, is the most similar to T. weiterschani, differing in the shape of dorsolateral idiosomal setae (only significant T. if weiterchani holotype is an adult female) and distribution of setulae on the setae h 2 – h 8: present only in basal part in T. coleogynis, evenly distributed throughout the length T. in weiterschani.
description: Published as part of Sidorchuk, Ekaterina A. & Khaustov, Alexander A., 2018, Two Eocene species of peacock mites (Acari: Tetranychoidea: Tuckerellidae), pp. 99-115 in Acarologia 58 (1) on pages 101-106, DOI: 10.24349/acarologia/20184228, http://zenodo.org/record/4487577