Machadocepheus pararachii, Ermilov & Khaustov, 2020

Ermilov, Sergey G. & Khaustov, Alexander A., 2020, New Species Of The Genera Diplobodes And Machadocepheus (Acari, Oribatida, Carabodidae) From Thailand, With Remarks On Some Related Genera, Acta Zoologica Academiae Scientiarum Hungaricae 66 (1), pp. 1-15 : 7-11

Machadocepheus pararachii sp. n.

( Figs 3A–C , 4A–D , 5D–F )

Diagnosis. Body size 481–564 × 282–332. Notogaster foveolate. Translamella present. Rostral setae spinose. Lamellar and interlamellar setae setiform, roughened. Bothridial setae with slightly developed lanceolate head, heavily barbed. Broad and deep depression in anterior half of notogaster and median notogastral hump-like process well developed. Notogaster with 15 pairs of notogastral setae short, setiform, roughened; of these, c 1, c 2, dp and la located in anterior notogastral depression, c 3 located on humeral shoulders, dm, lm, dp, lp, h 1 and h 2 located on hump-like process, and setae p 1 - p 3 and h 3 in posterolateral position. Epimeral setation 3–1–3–3; 1a, 1c, 2a and 3a minute, 1b, 3b, 3c, 4a, 4b and 4c of medium size, setiform, roughened. Anogenital region with specific system of anogenital depressions. Anal setae short, spiniform, other anogenital setae of medium size, setiform, roughened.

Description. Measurements. Body length 481 (holotype: male), 514, 564 (two paratypes: male and female, respectively); notogaster width 282 (holotype), 298, 332 (two paratypes: male and female, respectively).

Integument ( Figs 3A–C , 4A, C, D ). Body color brown. Body covered by thick layer of gel-like cerotegument. Body surface (including subcapitular mentum and genae, genital and anal plates) microgranulate (diameter of tubercles less than 1). Prodorsum, notogaster, circummarginal region of ventral plate, subcapitulum and antiaxial part of all leg femora sparsely foveolate (diameter of foveoles up to 8). Projecting parts of lamellae foveate.

Prodorsum ( Figs 3A–C ). Rostrum broadly rounded. Lamellae long (slightly shorter than prodorsum), distally with triangular projection. Translamella broad. One pair of interlamellar hump-like processes well developed, connected anteriorly by thick, transverse ridge. Basal part of prodorsum with median depression. Tutoria long, strong, ridge-like, reaching lateral margins of prodorsum. With depressions between lamellae, tutoria and pedotecta I ( Fig. 2C ). Rostral setae (32–36) thick, with numerous spines. Lamellar and interlamellar setae similar in length (16), setiform, roughened; le located on lamellae, in located on hump-like processes. Bothridial setae (45–53) with slightly developed lanceolate head, heavily barbed, curved semiovally in mediodistal part. Bothridia slightly interrupted ventrally. Exobothridial setae and their alveoli not observed.

Notogaster ( Figs 3A, 3C , 5D, 5F ). Furrow between prodorsum and notogaster absent. Anterior notogastral margin almost straight, posterior notogastral margin broadly rounded. Broad and deep depression in anterior half of notogaster and median notogastral hump-like process well developed. Hump-like structure with slight, numerous longitudinal wrinkles, forming partially reticulate pattern. Notogaster with 15 pairs of notogastral setae (16) setiform, roughened; of these, c 1, c 2, dp and la located in depression, c 3 located on humeral shoulders, dm, lm, dp, lp, h 1 and h 2 located on hump-like process, and setae p 1 – p 3 and h 3 in posterolateral position. Circumlateral depressions slightly developed. Lyrifissures ia not observed, other lyrifissures and opisthonotal gland openings well visible; im located lateral to la, gla lateral to lm, ip between p 1 and p 2, ips and ih on lateral sides of notogaster.

Gnathosoma ( Figs 3B, 3C ). Typical for Carabodidae ( ERMILOV & CORPUZ-RAROS 2016, ERMILOV & STARÝ 2018, ERMILOV et al. 2019). Subcapitulum longer than wide (123–131 × 77–90). Subcapitular setae (a 12–14; m 12–14; h 8–10) setiform, similar in thickness, roughened. Postpalpal setae (8) spiniform. Palps (77–77) with setation 0–2–1–3–9(+ω). Solenidion of palptarsi long, bacilliform. Chelicerae (123–131) with two setiform, barbed setae, cha (41) longer than chb (16). Trägårdh’s organ of chelicerae elongate triangular.

Epimeral and lateral podosomal regions ( Figs 3B, 3C , 5E, 5F ). Epimeral setation 3–1–3–3. Epimeral setae 1a, 1c, 2a and 3a minute (4), spiniform, 1b, 3b, 3c, 4a, 4b and 4c (16) setiform, roughened, often located in round cluster of granules. Pedotecta II rounded in ventral view. Discidia triangular, rounded distally. With one small depression behind acetabula IV and with one large elongate depression on lateral sides (between genitoaggenital region and notogastral margin).

Anogenital region ( Figs 3B, 3C , 5E ). With specific system of anogenital depressions ( Fig. 3B ): one pair of depressions removed and lateral to genital aperture; one pair of depressions removed and lateral to aggenital region. Thick transverse ridge located posterior to genital aperture. Usually with slightly visible, thin, diagonal furrows lateral to genital aperture. Four pairs of genital (12), one pair of aggenital (16) and three pairs of adanal (16) setae setiform, roughened. Two pairs of anal setae (8) spiniform. Adanal lyrifissures removed from anal aperture and located close to ad 3. Circumventral ridge visible.

Legs ( Figs 4A–D ). Claw of each leg strong, sparsely barbed dorsally and with one tooth ventrobasally. Porose area on all femora visible; porose area on trochanters not observed. Formulas of leg setation and solenidia: I (1–4–3–4–16) [1–2–2], II (1–4–3–3–15) [1–1–2], III (2–3–1–2–15) [1–1–0], IV (1–2–2–2–11) [0–1–0]; homology of setae and solenidia indicated in Table 1 . Famulus of tarsi I short, erect, blunt-ended, inserted posterior to solenidion ω 1. Solenidion Φ 1 on tibiae I very long, setiform; ω 1 and ω 2 on tarsi I, Φ 2 on tibiae I and σ on genua I, II of medium size, slightly thickened, blunt-ended; other solenidia short, bacilliform. Dorsoanterior apophysis of tibiae I (bearing Φ 1) developed.

Material examined. Holotype (male) and two paratypes (male and female): southwest Thailand, Phuket Province, close to Karon Beach , 7°49’32.8”N 98°17’46.5”E, litter in forest vegetation, 4.04.2017 (A. A. Khaustov).

Type deposition. The holotype is deposited in the collection of the Senckenberg Museum of Natural History, Görlitz, Germany. Two paratypes are deposited in the collection of the Tyumen State University Museum of Zoology, Tyumen, Russia. All in ethanol with a drop of glycerol.

Etymology. The species name pararachii refers to the similarity between the new species and Machadocepheus rachii Fernandez, Theron, Rollard et Leiva, 2014 .

Remarks. Machadocepheus pararachii sp. n. is morphologically most similar to Machadocepheus rachii Fernandez, Theron, Rollard et Leiva, 2014 from Gabon (see FERNANDEZ et al. 2014) in having well developed prodorsal and notogastral hump-like structures, a deep, smooth notogastral depression, and the presence of 15 pairs of short notogastral setae. However, the new species differs from the latter by the localization of notogastral setae c 1, da and la in the notogastral depression (versus on the hump-like process).

Figures

Fig. 3. Machadocepheus pararachii sp. n., adult: A = dorsal view, B = ventral view (legs not shown), C = lateral view (legs not shown). Scale bar: 100 µm

Fig. 4. Machadocepheus pararachii sp. n., adult: A = leg I, without trochanter, right, antiaxial view, B = leg II, without trochanter and tarsus, right, antiaxial view, C = leg III, without tarsus, right, antiaxial view, D = leg IV, right, antiaxial view. Scale bar: 20 µm

Fig. 5. Diplobodes parakanekoi sp. n. (A–C) and Machadocepheus pararachii sp. n. (D–F), adult, microscope images: A, D = dorsolateral view; B, E = ventral view; C, F = lateral view

Fig. 2. Diplobodes parakanekoi sp. n., adult: A = leg I, without trochanter, right, antiaxial view, B = leg II, without trochanter and tarsus, left, antiaxial view, C = leg III, without tar- sus, left, antiaxial view, D = leg IV, left, antiaxial view. Scale bar: 20 µm