Malgacheliodes martensi, Ermilov & Hugo-Coetzee & Khaustov, 2021

Ermilov, Sergey G., Hugo-Coetzee, Elizabeth A. & Khaustov, Alexander A., 2021, Malgacheliodes martensi spec. nov. (Acari, Oribatida, Licnodamaeidae) from South Africa, Zootaxa 4984 (1), pp. 357-367 : 360-364

Malgacheliodes martensi spec. nov.

Figs 1–6

Diagnosis. Adult. Body size: 581–713 × 348–431. Anogenital region completely with strong diagonal ribs separated by narrow furrows. Rostral and lamellar setae long, setiform, slightly barbed. Interlamellar seta minute, spiniform. Bothridial seta long, with elongate flattened head, spiculate. Notogaster with four pairs of setiform, roughened setae (h 1 absent). Epimeral and anogenital setae comparatively short, setiform, roughened. Leg tracheae bacilliform. Lateral seta on some leg segments slightly phylliform. Tritonymph. Dorsal part of prodorsum foveate; gastronotum and ventral side of body folded. Propodolateral apophysis present. Bothridial seta long, with elongate flattened head, spiculate. Five pairs of gastronotic setae developed, seta h 1 inserted on posterior gastronotic apophysis. Epimeral and anogenital setae short, setiform, smooth.

Description of adult. Measurements. Body length: 713 (holotype), 581–713 (11 paratypes); body width: 431 (holotype), 348–431 (11 paratypes). Females larger than males: 680–713 × 415–431 versus 581–664 × 348–415.

Integument ( Figs 1A, B ; 2B ; 4A–C ). Body color brown. Body and legs covered by thick cerotegumental layer represented by tubercular and bacillar structures (length up to 8). Rostrum, subcapitular mentum and epimeres partially foveate. Prodorsum with system of ridges. Notogaster foveolate (diameter of foveola up to 12). Anogenital region with strong diagonal ribs separated by narrow furrows. Epimeral borders and anogenital ribs slightly and densely striate. Genital and anal plates with long, sparse, longitudinal furrows. Posterior notogastral part with short, narrow, longitudinal depressions. Setae with or without cerotegument.

Prodorsum ( Figs 1A , С; 4A, B). Rostrum broadly rounded. Enantiophysis well developed, both tubercles simple. Propodolateral apophysis strong, thorn-like. Rostral (77–82) and lamellar (65–69) setae setiform, slightly barbed. Interlamellar seta (10–12) spiniform, smooth. Bothridial seta (135–143) with elongate flattened head, spiculate. Exobothridial seta (4) setiform, thin, smooth.

Notogaster ( Figs 1A–C ; 2A ; 4A, B ). Oval. Exuvial scalps always present. Marginal notogastral zone slightly depressed. Four pairs of setiform, roughened setae developed (lp, p 1 – p 3, 32–36). Opisthonotal gland opening and all lyrifissures distinct.

Gnathosoma ( Figs 2B–D ). Subcapitulum longer than wide (135–143 × 94–102). Subcapitular seta a (16–20), setiform, shortly ciliate; setae m and h (both 24–28) setiform, slightly barbed. Adoral seta (12–16) setiform, thin, slightly barbed. Transverse ridge on subcapitular mentum well developed. Palp (73) with typical setation 0-2-1-3- 9(+ω). Postpalpal seta (8) spiniform, roughened. Chelicera (127–139) with two setiform, barbed setae (cha, 45–49; chb, 28–32).

Epimeral and lateral podosomal regions ( Figs 1B, C ; 4C ). Epimere I with median elongate trapezoid depression. Epimeral setal formula 3-1-3-3. All epimeral setae (20–28) setiform, thin, roughened. Parastigmatic tubercle Sa small, tubercle-like, Sp not observed. Discidium strong, tubercle-like.

Anogenital region ( Figs 1B, C ; 2A ; 4C ). Genital, aggenital, anal, and adanal setae (all 20–28) setiform, thin, roughened. Adanal lyrifissure not observed.

Legs ( Figs 3A–D ). Median claw thicker than lateral claws, all roughened on dorsal side. Tarsus I with dorsal carina bearing two solenidia and famulus. Tibia I with dorsodistal cylindrical apophysis bearing two solenidia and seta. Tarsi II–IV and tibiae II–IV with (dorsal and dorsodistal, respectively) strong dorsodistal carina forming apically triangular process. All femora with ventral keel rounded anteriorly. Porose area on all leg segments not observed. All femora and trochanters III, IV with bacilliform trachea. Formulas of leg setation and solenidia: I (1- 5-4-5[6]-20) [1-2-2], II (1-5-4-4[5]-16) [1-1-2], III (2-3-3-4-15) [1-1-0], IV (1-3-2-4-12) [0-1-0]; homologies of setae and solenidia indicated in Table 1 . Famulus on tarsus I well visible, sunken in cup-like cuticular deepening, short, erect, slightly swollen distally. Setae p on tarsus I eupathidial versus setiform on tarsi II–IV. Seta s on tarsus I setiform, barbed (not eupathidial). Seta l’ on tibiae III, IV, genua II, IV, femora III, IV, and seta l” on genu II, femur II slightly phylliform. Solenidia φ 1 (coupled with dorsal seta) and φ 2 on tibia I setiform, other solenidia slightly thickened, rounded apically.

Description of tritonymph. Measurements. Total length: 597–647 (three tritonymphs); maximum width: 365– 398 (three tritonymphs).

Integument ( Figs 5A, B ; 6A–C ). Cuticle of prodorsum, subcapitulum, legs, and posterior part of gastronotum brown, other cuticle light brown. Body and legs covered by thick cerotegumental layer represented by tubercular and bacillar structures (length up to 6). Gastronotum (except dorsocentral part), ventral side of body and lateral side of prodorsum folded. Subcapitular mentum, lateral part of epimeres and dorsal (except basal part) and anterolateral parts of prodorsum partially foveate. Prodorsum with system of ridges. Setae with or without cerotegument.

Prodorsum ( Figs 5A ; 6A, C ). About 1/2 length of gastronotic region. Rostrum broadly rounded. Enantiophysis not developed. Propodolateral apophysis strong, thorn-like. Rostral (57–61) and lamellar (49–53) setae setiform, roughened. Interlamellar seta (6–8) spiniform, smooth. Bothridial seta (135–143) with elongate flattened head, spiculate. Exobothridial seta (16) setiform, thin, smooth. Basal part of prodorsum with one pair of transverse, elongate oval porose areas.

Gastronotic region ( Figs 5A, B ; 6A, C ). Gastronotum carrying scalps of previous instars, triangular posteriorly, with posterior gastronotic apophysis bearing setae h 1. Five pairs of gastronotic setae present: seta h 1 (131–143) narrowly phylliform, spiculate; setae lp, p 1 (45–57) and p 2, p 3 (16–20) setiform, thin, smooth. Opisthonotal gland opening and all cupules (except ip not observed) slightly visible.

Gnathosoma . Mostly similar to adult. Subcapitulum with the same length and width (106–110 × 106–110). Subcapitular (16) and adoral (8) setae setiform, thin, smooth. Transverse ridge on subcapitular mentum absent. Palp (65) with setation 0-2-1-3-9(+ω). Postpalpal seta (6) spiniform, smooth. Chelicera (106–110) with two setiform, barbed setae (cha, 36; chb, 20).

Epimeral region ( Figs 5B ; 6B, C ). Epimeral setal formula 3-1-3-3. All epimeral setae (16) setiform, thin, smooth. Tubercles of parastigmatic enantiophysis not developed. Discidium present, tubercle-like.

Anogenital region ( Figs 5B ; 6B, C ). Seven pairs of genital, one pair of aggenital, three pairs of anal, and three pairs of adanal setae (all 16) setiform, thin, smooth. Opisthonotal gland opening and all cupules slightly visible.

Legs. Mostly similar to adult. Claw of each leg strong, roughened on dorsal side. Tarsi I–IV with dorsal triangular process; tibiae II–IV without such process. Tibia I with dorsodistal cylindrical apophysis bearing two solenidia and seta. All femora without ventral pteromorph-like keel. All tarsi, tibiae and genua with posterior collar-like tectum. Trachea and porose area on segments not observed. Formulas of leg setation and solenidia: I (1-5-4-5-18) [1-2-2], II (1-5-4-4-15) [1-1-2], III (2-3-3-4-15) [1-1-0], IV (1-3-2-4-12) [0-1-0]; homologies of setae and solenidia indicated in Table 1 . Famulus on tarsus minute, sunken in cup-like cuticular deepening. Setae p on tarsus I eupathidial versus setiform on tarsi II–IV. Seta s on tarsus I setiform, barbed (not eupathidial). Solenidia φ 1 (coupled with dorsal seta) and φ 2 on tibia I setiform, other solenidia slightly thickened, slightly rounded apically.

Material examined. Holotype (female), 11 paratypes (eight males and three females) and three tritonymphs: South Africa, Amathole mountains in the Eastern Cape Province, Hogsback State Forest at the village of Hogsback, 32°35’21.6”S, 26°57’38.5’’E, indigenous Afromontane mixed forest ( Mucina & Geldenhuys 2006), consisting of tall trees (dominant species, e.g. Afrocarpus falcatus (yellowwood), Celtis africana (white stinkwood), Calodendrum capense (Cape chestnut) and Vepris lanceolata (white ironwood)) and a dense understorey of shrubs, herbs and moss, in soil, 14.IX.2019 (collected by V.A. Khaustov, S.G. Ermilov, E.A. Hugo-Coetzee, and A.A. Khaustov).

Type deposition. The holotype (female) is deposited in the collection of the National Museum Bloemfontein, South Africa ( NMB); 11 paratypes (eight males and three females) and three tritonymphs are deposited in the collection of the Tyumen State University Museum of Zoology, Tyumen, Russia ( TSUMZ). All specimens are preserved in 70% solution of ethanol with a drop of glycerol.

Etymology. The species name is dedicated to our friend and colleague, the well-known zoologist Dr. Jochen Martens (Johannes Gutenberg Universität, Mainz, Germany).

Differential diagnosis. Adults of M. martensi spec. nov. morphologically most similar to those of the type species ( M. guillaumeti ) in many traits (e.g., notogaster foveolate; anogenital region with diagonal ribs and furrows; prodorsum with enantiophysis; propodolateral apophysis present; bothridial seta long, with elongate flattened head), but differs from the latter by the presence of diagonal ribs with narrow furrows in-between in the aggenital region (versus aggenital ribs and furrows absent), bacilliform leg tracheae (versus tracheae setiform), rounded ventral keel on leg femur I (versus keel triangular) and four pairs of notogastral setae, h 1 absent (versus five pairs including h 1). Tritonymphs of M. martensi spec. nov. differs from that of M. guillaumeti by the presence of five pairs of gastronotic setae, c 1 absent (versus six pairs including c 1).

Figures

FIGURES 1A–C. Malgacheliodes martensi spec. nov., adult: A Dorsal view (exuvial scalps and legs not shown). B Ventral view (legs not shown). C Lateral view (exuvial scalps and legs not shown). Scale bar: 100 μm.

FIGURES 2A–D. Malgacheliodes martensi spec. nov., adult. A Posterior view (exuvial scalps not shown). B Subcapitulum, ventral view. C Palp, left, paraxial view. D Chelicera, right, antiaxial view. Scale bars: 100 μm (A), 20 μm (B–D).

FIGURES 3A–D. Malgacheliodes martensi spec. nov., adult.A Leg I, left, paraxial view. B Leg II, without tarsus, right, antiaxial view. C Leg III, without tarsus, left, antiaxial view. D Leg IV, left, antiaxial view. Scale bar: 50 μm.

FIGURES 4A–C. Malgacheliodes martensi spec. nov., adult, microscope images. A Dorsal view (without exuvial scalps). B Dorsal view (with exuvial scalps). C Ventral view. Magnification: 600x.

FIGURES 5A–B. Malgacheliodes martensi spec. nov., tritonymph. A Dorsal view (exuvial scalps and legs not shown). B Ventral view (legs not shown). Scale bar: 100 μm.

FIGURES 6A–C. Malgacheliodes martensi spec. nov., tritonymph, microscope images.A Dorsal view (without exuvial scalps). B Ventral view. C Lateral view. Magnification: 600x.