1✉ Institute of Environmental and Agricultural Biology (X-BIO), Tyumen State University, Tyumen, Russia.
2Institute of Zoology, Slovak Academy of Sciences, Bratislava, Slovakia.
2019 - Volume: 59 Issue: 4 pages: 456-474
https://doi.org/10.24349/acarologia/20194348This work is based on the random set of the Malaysian oribatid mite (Acari, Oribatida) material, which was received from the collection of the Institute of Zoology (Slovak Academy of Sciences, Bratislava, Slovakia), and includes data on the family Otocepheidae.
In the course of taxonomic identification we found two otocepheid species, one species belonging to the genus Fissicepheus Balogh and Mahunka, 1967 is new to science, and the other is a known species, Leptotocepheus murphyi (Mahunka, 1989); both are from the nominative subgenera.
The primary goal of our paper is to describe and illustrate a new species under the name Fissicepheus parastriganovae n. sp. Fissicepheus was described by Balogh and Mahunka (1967), with Fissicepheus elegans Balogh and Mahunka, 1967 as type species. The genus comprises two subgenera and 27 species (Subías 2019). The generic diagnosis was presented by Balogh and Mahunka (1967) and Aoki (1967). The nominative subgenus comprises 26 species, which are distributed in the Palaearctic and Oriental regions (Subías 2019). An identification key to known species of the subgenus is provided by Zheng and Chen (2018).
The secondary goal of our paper is to present a supplementary description of L. murphyi, adding new figures and information about morphological variability and some morphological structures and their measurements, identification of leg setae and solenidia and morphology of the gnathosoma, which will assist with identification of this species in the future. Leptotocepheus murphyi was found earlier in Singapore and Vietnam (Mahunka 1989; Ermilov and Bayartogtokh 2015). Thus, it is the first finding of this species in Malaysia.
Specimens were mounted in lactic acid on temporary cavity slides for measurement and illustration. Body length was measured in lateral view, from the tip of the rostrum to the posterior edge of the notogaster. Notogastral width refers to the maximum width of the notogaster in dorsal view. All body measurements are presented in micrometers. Formulas for leg setation are given in parentheses according to the sequence trochanter-femur-genu-tibia-tarsus (famulus included). Formulas for leg solenidia are given in square brackets according to the sequence genu-tibia-tarsus.
Drawings were made with a camera lucida using a Leica transmission light microscope ''Leica DM 2500''. SEM photos were made with the aid of a JEOL–JSM-6510LV SEM microscope.
Morphological terminology used in this paper follows that of F. Grandjean: see Travé and Vachon (1975) for references, Norton (1977) for leg setal nomenclature, and Norton and Behan-Pelletier (2009), for overview.
The following abbreviations are used in this paper: cos – costula; rr – rostral ridge; ro, le, in, bs, ex – rostral, lamellar, interlamellar, bothridial and exobothridial setae, respectively; cpm, cpl – medial and lateral prodorsal condyles, respectively; cnm, cnl, cn – medial, lateral and additional medial notogastral condyles, respectively; c, la, lm, lp, h, p – notogastral setae; ia, im, ip, ih, ips – notogastral lyrifissures; gla – opisthonotal gland opening; a, m, h – subcapitular setae; v, l, d, cm, acm, ul, sul, vt, lt – palp setae; ω – palp and leg solenidion; cha, chb – cheliceral setae; Tg – Trägårdh's organ; PdI, PdII – pedotecta I, II, respectively; 1a, 1b, 1c, 2a, 3a, 3b, 3c, 4a, 4b, 4c – epimeral setae; dis – discidium; g, ag, an, ad – genital, aggenital, anal and adanal setae, respectively; iad – adanal lyrifissure; cvr – circumventral ridge; pa – porose area po – preanal organ; Tr, Fe, Ge, Ti, Ta – trochanter, femur, genu, tibia, tarsus, respectively; pa – porose area; σ, φ – leg solenidia; ɛ – leg famulus; v, ev, bv, l, d, ft, tc, it, p, u, a, s, pv – leg setae.
Type species Fissicepheus elegans Balogh and Mahunka, 1967
ZOOBANK: 4C1C6354-6DBD-4543-BE2C-F99371B4E84F
(Figures 1–7)
Diagnosis — Body size: 166–232 × 597–647. Body surface punctate, anal plates and medioposterior part of notogaster foveolate. Rostral and lamellar setae long, setiform, slightly barbed. Interlamellar and 10 pairs of notogastral setae of medium size, phylliform, slightly barbed. Bothridial setae long, fusiform or clavate, barbed. Lateral and medial prodorsal and notogastral condyles tubercle-like, simple. Epimeral setal formula 2-0-2-3. Epimeral and genitoaggenital setae setiform, slightly barbed. Adanal and anal setae phylliform, slightly barbed. Adanal lyrifissures distanced from anal aperture. Leg genua III and IV without seta l'. Setae u setiform on all leg tarsi.
Description — Measurements – Body length: 498 (holotype: male), 464–647 (seven paratypes: three females and four males); notogaster width: 182 (holotype), 166–232 (seven paratypes). Length/width ratio 2.7–2.8. Females larger than males: 597–647 × 199–215 versus 464–514 × 166–182.
Integument (Figs 1a, 1b, 2b, 3b, 4a, 5a, 6a, 7c) – Body color light brown, but legs, apodemes and anterior part of chelicerae dark brown. Body covered by layer of colorless, gel-like cerotegument. Body surface punctate. In addition, anal plates and medioposterior part of notogaster (between setae lm and h1) sparsely foveolate (diameter of foveolae up to 4 and 2, respectively). Costulae partially foveolate. Lateral parts of body (between bothridia and acetabula I–III) without tubercles. Antiaxial side of all leg femora and trochanters III, IV with microgranules.
Prodorsum (Figs 1a, 2a, 5a-c, 7a, 7b) – Rostrum broadly rounded. Anterior part of prodorsum with strong transverse ridge. Costulae well developed, long, reaching bothridia basally and lamellar setae distally. Tutorial ridges and lateral carinae absent. Rostral (57–51) and lamellar (65–69) setae setiform, slightly barbed (poorly visible), curving and directed anteromedially. Interlamellar setae (24–32) phylliform, slightly barbed. Exobothridial setae (8–10) setiform, thin, smooth. Bothridial setae (length outside bothridia 65–73) with long, smooth stalk and shorter, fusiform or clavate, barbed head. Paired lateral and paired medial prodorsal condyles tubercle-like, located separately.
Notogaster (Figs 1a, 1b, 2a, 2b, 5a-c, 6a, 7c) – Paired lateral and paired medial notogastral condyles tubercle-like, without fusions, located separately. Circumdorsal part of notogaster slightly depressed (Figs 5a, 5b). Circumgastric sigillar band visible. Notogaster with 10 pairs (45–49) of phylliform, slightly barbed setae. Lyrifissures and opisthonotal gland openings distinct, ia located lateral to c, im and gla close to each other, lateral to lm, ip between p2 and p3, ips and ih anterior to h3.
Gnathosoma (Figs 1b, 2a, 6a) – Generally, similar to L. murphyi. Subcapitulum longer than wide (114–123 × 73–82). Subcapitular setae setiform, barbed, a (28–30) shorter than m and h (36–41). Adoral setae and their alveoli absent. Palps (73–77) with typical setation 0-2-1-3-8(+ω). Postpalpal setae (6) spiniform, smooth. Chelicerae (135–139) with two setiform, barbed setae, cha (45–49) longer than chb (16–20). Trägårdh's organ of chelicerae elongate triangular.
Epimeral and lateral podosomal regions (Figs 1b, 2a, 5b, 6a, 6b) – Apodemes I, II, III and sejugal apodemes distinct. Sternal apodeme not developed. Condyles of epimere IV well developed. Epimeral setal formula 2-0-2-3, setae setiform, slightly barbed, 1b (45–49) longer than 3b (36–41) and others (28–32); 1a, 2a, 3a and their alveoli absent. Pedotecta I and II represented by small lamina. Discidia tubercle-like.
Anogenital region (Figs 1b, 2a, 2b, 5b, 6a, 6b) – Aggenital lyrifissures not visible. Four pairs of genital (16–20) and one pair of aggenital (24–32) setae setiform, slightly barbed. Three pairs of adanal setae (36–41) narrowly phylliform, slightly barbed; ad3 located lateral to anal plates and removed from them. Two pairs of anal setae (24–32) slightly dilated basally, with setiform mediodistal part, slightly barbed. Adanal lyrifissures transverse or diagonal, distanced from anal aperture, located anterior to insertions of adanal setae ad3. Circumventral ridge well developed.
Legs (Figs 3a, 3b, 4a, 4b, 5b, 6a) – Claw of each leg strong, slightly barbed dorsally. Tarsi with one pair of very small teeth on dorsal side. Porose areas present on all femora and on trochanters III, IV (well visible in dissected specimens). 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 (2-3-0-2-15) [1-1-0], IV (1-2-1-2-12) [0-1-0]; homology of setae and solenidia indicated in Table 1. Solenidia φ1 and φ2 on tibiae I, φ on tibiae II, σ on genua I, II setiform, others bacilliform. Famulus of tarsi I short, erect, distally blunt, inserted posterior to solenidia. Setae u setiform on all tarsi.
Material examined — Holotype (male) and seven paratypes (three females and four males): Malaysia, Perak District, 50 km NE to Gerik, Titiwangsa, 05°36'17.4''N, 101°32'34.0''E, alt. 1100 m, forest complex Belum–Temenggor, litter, 30 March–13April 2015 (E. Jendek & O. Šauša).
Type deposition — The holotype is deposited in the collection of the Institute of Zoology, Slovak Academy of Sciences, Bratislava, Slovakia; five paratypes are deposited in the collection of the Tyumen State University Museum of Zoology, Tyumen, Russia. All in ethanol with drop of glycerol.
Etymology — The species name refers to the similarity of the new species to Fissicepheus striganovae Ermilov and Anichkin, 2014.
Remarks — Fissicepheus parastriganovae n. sp. is morphologically most similar to Fissicepheus striganovae Ermilov and Anichkin, 2014 from Vietnam in having simple costulae, phylliform interlamellar, notogastral and adanal setae, and long bothridial setae, and the development of all prodorsal and notogastral condyles; it differs from the latter by the presence of partial foveolate body ornamentation (only on anal plates and in medioposterior part of notogaster versus prodorsum, notogaster and anogenital region completely foveolate), interlamellar setae clearly shorter than notogastral setae (versus similar in length) and more long notogastral setae (45–49 versus 24–32), and the absence of longitudinal stria on genital plates (versus present).
Type species Leptotocepheus trimucronatus Balogh, 1961
(Figures 8–13)
Supplementary description — Measurements – Body length: 630–946 (21 specimens: 11 females and 10 males); notogaster width: 232–398 (21 specimens). Length/width ratio 2.3–2.7. Females larger than males: 813–946 × 365–398 versus 630–730 × 232–282.
Integument (Figs 8a, 8b, 9b, 9c, 12a-d, 13a, 13b) – Body color brown, but legs, genital plates, subcapitular genae and anterior part of chelicerae dark brown. Body covered by layer of colorless, gel-like cerotegument. Body surface microgranulate. In addition, prodorsum, notogaster, anogenital region and anterior part of ventral plate foveolate (diameter of foveolae up to 16); region between costulae sometimes slightly rugose. Costulae partially foveolate. Lateral parts of body (between bothridia and acetabula I–III) without tubercles (their diameter up to 8).
Prodorsum (Figs 8a, 9a-c, 12a-c, 13b, 13c) — Rostrum broadly rounded. Costulae well developed, long, reaching bothridia basally and lamellar setae distally. Tutorial ridges absent. One lateral carina between acetabulum I and insertion of rostral seta present on each side. Rostral (65–69) and lamellar (77–82) setae setiform, shortly ciliate on dorsal sides, curving and directed anteromedially. Interlamellar setae (98–110) thickened, barbed. Exobothridial setae (12–16) slightly thickened, smooth. Bothridial setae (length outside bothridia 94–98) with long, elongate, distinctly dilated mediodistally. Paired lateral prodorsal condyles tubercle-like, paired medial prodorsal condyles broadly rounded, all located separately.
Notogaster (Figs 8a, 8b, 9a-c, 12a-d) – Five notogastral condyles present: paired lateral, one unpaired median and additional paired medial notogastral condyles, all tubercle-like, without fusions, located separately. Unpaired median condyle sometimes weaker developed than additional medial notogastral condyles; also, it is absent in four males (Fig. 9a). Circumdorsal part of notogaster slightly depressed (Figs 12a, 12b). Circumgastric sigillar not visible. Notogaster with 10 pairs (82–94) thickened, barbed setae. Lyrifissures and opisthonotal gland openings distinct, ia located posterolateral to c, im and gla close to each other, posterolateral to la, ip between p2 and p3, ips and ih anterior to h3.
Gnathosoma (Figs 9d-f, 12b, 13a) – Subcapitulum longer than wide (172–176 × 123–127). Subcapitular setae setiform, barbed, a (24–28) shorter than m (49–53) and h (57–61). Adoral setae and their alveoli absent. Palps (94–102) with typical setation 0-2-1-3-8(+ω). Postpalpal setae (8) spiniform, smooth. Chelicerae (188–192) with two setiform, barbed setae, cha (57–61) longer than chb (20–24). Trägårdh's organ of chelicerae elongate triangular.
Epimeral and lateral podosomal regions (Figs 8b, 9b, 12b, 13a) – Apodemes I, II, III and sejugal apodemes distinct. Sternal apodeme not developed. Epimeral setal formula 3-1-3-3, setae setiform, slightly barbed, 1a, 2a, 3a, 4b and 4c (24–32) shorter than others (45–57). Pedotecta I represented by large lamina, pedotecta II represented by small lamina. Discidia elongate triangular.
Anogenital region (Figs 8b, 9b, 9c, 12b, 13a) – Aggenital lyrifissures not visible. Four pairs of genital (20–24) and one pair of aggenital (49–61) setae setiform, slightly barbed. Three pairs of adanal (57–59) and two pairs of anal (45–53) setae thickened, barbed. Adanal lyrifissures diagonal, slightly distanced from anal aperture, located between anal aperture and insertions of adanal setae ad3. Circumventral ridge present, but poorly visible (Fig. 12b).
Legs (Figs 10a, 10b, 11a, 11b, 12a, 12b, 13a, 13b) – Claw of each leg strong, slightly barbed dorsally. Tarsi with one pair of distinct teeth on dorsal side. Porose areas present on all femora and on trochanters III, IV (well visible in dissected specimens). 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 (1-2-2-2-12) [0-1-0]; homology of setae and solenidia indicated in Table 1. Solenidion φ1 on tibiae I setiform, others bacilliform. Famulus of tarsi I short, erect, distally blunt, inserted posterior to solenidia. Setae u setiform on tarsi I, II and spiniform on tarsi III, IV.
Material examined — Twenty one specimens (11 females and 10 males): Malaysia, Perak District, 50 km NE to Gerik, Titiwangsa, 05°36'17.4''N, 101°32'34.0''E, alt. 1100 m, forest complex Belum–Temenggor, litter, 30 March–13 April 2015 (E. Jendek & O. Šauša).
Remarks — Morphological traits – Based on the supplementary description and original description (Mahunka 1989), the following diagnostic morphological traits for L. murphyi are proposed:
Body size: 630–946 × 232–398. Body surface microgranulate; prodorsum, notogaster, anogenital region and anterior part of ventral plate foveolate. Rostral and lamellar setae long, setiform, shortly ciliate. Interlamellar and 10 pairs of notogastral setae long, thickened, barbed. Bothridial setae distinctly or slightly dilated mediodistally. Lateral prodorsal and lateral notogastral condyles tubercle-like, medial prodorsal condyles broadly rounded, three medial notogastral condyles (one pair of additional condyles and one median unpair condyle) tubercle-like. Epimeral and genitoaggenital setae setiform, slightly barbed. Adanal and anal setae thickened, barbed. Adanal lyrifissures diagonal. Setae u setiform on tarsi I, II and spiniform on tarsi III, IV.
Comparison – Our specimens of L. murphyi are morphologically identical to the Singapore specimens from the original description (Mahunka 1989). Only one slight difference is present: bothridial setae usually distinctly dilated mediodistally versus bothridial setae near setiform, slightly dilated in median part (only one our specimen has similar structure of bothridial setae).
Also, we have found that sometimes the median unpaired notogastral condyle is lacking in four males in Malaysia versus always developed.
Thus, these morphological nuances must be considered in future identifications of L. murphyi.
The otocepheid genera Leptotocepheus and Dolicheremaeus Jacot, 1938 are morphologically similar in many main traits except one: Leptotocepheus with unpaired median notogastral condyle versus this unpaired condyle always absent and instead of it the paired medial condyles often present in Dolicheremaeus.
Leptotocepheus murphyi was described by Mahunka (1989) as the representative of the genus Dolicheremaeus Jacot, 1938. Ermilov (2015) and Ermilov and Bayartogtokh (2015) used the new generic position for this species (genus Leptotocepheus), and, later, the new systematic placement of L. murphyi was supported by other authors (e.g., Subías 2016, 2019; Ermilov and Minor 2018). This confusion is connected with one important morphological nuance: the species is unusual because its anteromedial part of notogaster has simultaneously three tubercles (one median unpaired condyle, and paired medial condyles). Based only on the presence of the paired medial condyles, Mahunka (1989) included L. murphyi in Dolicheremaeus, сonsidering most likely that the unpaired median condyle is additional (not basic). On the contrary, Ermilov (2015) and Ermilov and Bayartogtokh (2015) considered that the unpaired median condyle is basic (paired medial condyles are additional, not basic), therefore, they included the species in Leptotocepheus.
Our data on morphology of the Malaysian specimens of L. murphyi show presence and absence (seldom) of unpaired median notogastral condyle in different specimens, and this situation creates additional confusion about which notogastral condyles to consider basic or additional (unpaired median condyle or paired medial condyles). Thus, in this moment, based on the presence of unpaired median notogastral condyle (in typical case), we continue to consider the species as representative of Leptotocepheus, but its placement may be revised in the future (for example, after genetic analysis).
We cordially thank Dr. Julia Baumann (University of Graz, Graz, Austria) and two anonymous reviewers for valuable comments; E. Jendek and O. Šauša who collected the oribatid mites; A.A. Gubin for SEM photos; and the Institute of Zoology, Slovak Academy of Sciences, Bratislava, Slovakia, which kindly provided material for our study. This paper was partially supported by the project VEGA 2/0139/17.
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