Wallworkoppia cervifer ( Mahunka, 1983 )

Ermilov, Sergey G., 2024, Taxonomic contribution to knowledge of the oribatid mite subfamily Arcoppiinae (Acari, Oribatida, Oppiidae), Ecologica Montenegrina 73, pp. 72-81 : 77-81

Wallworkoppia cervifer ( Mahunka, 1983)

( Figs 12–22 )

Material. Three specimens (two males and one female): eastern Guatemala, Izabal Department, Las Escobar, 8 km SW. Puerto Barrios , rainforest litter, 12–14.XI.1986 (E.E. Lindquist) .

The material is deposited in the collection of the Tyumen State University Museum of Zoology , Tyumen, Russia. All specimens are preserved in 70% solution of ethanol with a drop of glycerol .

Supplementary description of adult. Measurements. Body length: 270–285 (males), 300 (female); body width: 150–157 (males), 165 (female).

Integument. Body color light brown. Body surface mostly smooth but lateral side of body between bothridium and acetabula I– III densely tuberculate (diameter of tubercle up to 4); basal part of prodorsum with one pair of short longitudinal ridges; tubercle band located instead mediobasal part of costula.

Prodorsum. Rostrum tripartite, with rounded median part and longer triangular lateral ones. Costulae and transcostula poorly observable, fused, forming trapezoid costular-transcostular complex; costula short, its mediobasal part not developed. Specific ridge-like structure (similar to an arch with triangular narrowness anteriorly) present in front of transcostula. Rostral (30–34), lamellar (22–26) and interlamellar (34–41) setae setiform, slightly barbed; exobothridial seta (19–22) setiform, roughened; bothridial seta (52–56) pectinate, with five long, slightly barbed branches; proximal branches longer than distal branches. Interbothridial and postbothridial tubercles absent. Three pairs of interbothridial muscle sigillae well observable, located oblique.

Notogaster . Anterior notogastral margin convex. All notogastral setae (c: 19; p 1: 22–30; h 1, p 2, p 3: 34–41; la, lm, lp, h 2, h 3: 52–64) setiform, slightly barbed to well barbed; la located posterolateral to lm. Opisthonotal gland opening and lyrifissures ia, im, ip distinct; lyrifissures ih and ips not observable.

Gnathosoma. Subcapitulum size: 64–67 × 45–49; all subcapitular setae (22–30) setiform, slightly barbed; both adoral setae (7) setiform, smooth. Palp length: 41–45; setation: 0–2–1–3–9(+ω); solenidion long (3/4 of tarsus), slightly bacilliform, pressed to surface; postpalpal seta (5) spiniform, smooth. Chelicera length: 64–67; setae (cha: 19–22; chb: 13–15) setiform, barbed.

Epimeral and lateral podosomal regions. Epimeral formula: 3–1–3–3; all setae (1c: 11–13; 1a, 2a, 3a: 13–15; 1b, 3b, 4b: 17–19; 4a, 4c: 26–34; 3c: 36–45) setiform, slightly barbed. Discidium rounded.

Anogenital region. Anogenital formula: 6–1–2–3; all genital setae (9) setiform, roughened; aggenital (13–15), anal (13–15) and adanal (ad 1: 17–19; ad 2, ad 3: 19–22) setae setiform, slightly barbed. Adanal lyrifissure close and parallel to anal aperture.

Legs. Claw of each leg smooth. Trochanter III with several lateral and posterior teeth. Formulas of leg setation and solenidia: I (1–5–2–4–20) [1–2–2], II (1–5–2–4–16) [1–1–2], III (2–3–1–3–15) [1– 1–0], IV (1–2–2–3–12) [0–1–0]; homology of setae and solenidia indicated in Table 1; setae p’ and p” setiform on tarsus I versus short, conical (poorly observable) on tarsi II–IV; seta s eupathidial on tarsus I; seta pv” on tarsus IV modified, brush-like; solenidia ω 1 on tarsus I, ω 1, ω 2 on tarsus II, φ on tibia II, and σ on genu III medium-sized, slightly bacilliform; ω 2 on tarsus I and φ 2 on tibia I medium-sized, rodlike; other solenidia long, subflagellate.

Remarks. Adults of W. cervifer from Guatemala are morphologically similar to those from Mexico described by Mahunka (1983), except slightly smaller body size (270–300 × 150–165 versus 324–335 × 169–180). We believe that this size difference represents intraspecific variability.

Based on our supplementary description and on the original description ( Mahunka 1983) of adult, we propose the following diagnostic morphological traits for W. cervifer : Body length: 270–335. Rostrum tripartite, median part rounded, shorter than lateral ones. Costulae and transcostula forming poorly observable trapezoid complex; mediobasal part of costula not developed. Specific ridge-like structure present in front of transcostula. Basal part of prodorsum with one pair of short longitudinal ridges. Rostral, lamellar and interlamellar setae setiform, slightly barbed; of these, le shortest, in longest; bothridial seta pectinate, with five long, slightly barbed branches. All notogastral setae setiform, slightly barbed to well barbed; c well observable; la, lm, lp, h 2, h 3 similar in length, comparatively long; other setae short; la located posterolateral to lm. Discidium rounded. Adanal lyrifissure close and parallel to anal aperture.

Discussion

1. Arcoppia and Wallworkoppia Subías, 1989 were created as the independent genera by Hammer (1977) and Subías and Balogh (1989), respectively. In general appearance, they are morphologically similar, but differ from each other by one trait (bothridial seta with well-developed head in Arcoppia versus without developed head in Wallworkoppia ). Therefore, the support of the generic status of Wallworkoppia is difficult. For example, it was lowered to the subgeneric status within Arcoppia (e.g., Mahunka & Mahunka-Papp 2007; Ermilov et al. 2014), or the species of Wallworkoppia are considered as typical representatives of Arcoppia without mention of Wallworkoppia (e.g., Balogh & Balogh 1990, 1992).

The modern Subías’s system of Oppiidae ( Subías 2022; Subías & Shtanchaeva 2023; after Subías & Balogh 1989) uses the morphology of the bothridial seta between related taxa inconsistently, i.e., sometimes supported generic status, but sometimes accepted only subgeneric status. Arcoppia tetraramosa and W. cervifer are morphologically very similar (especially in the presence of specific ridge-like structure on the prodorsum), and their placement in different genera looks strange. Therefore, most likely, it would be more logical to consider Wallworkoppia as a subgenus within Arcoppia .

2. Arcoppia longiramosa ( Wallworkoppia longiramosa in the modern sense) was described by Woas (1986) from Salvador. Later, Balogh and Balogh (1990) synonymized it with Arcoppia cervifer ( W. cervifer in the modern sense) from Mexico. This synonymy was supported (e.g., Subías 2004, 2022; Ermilov et al. 2014). Perhaps, the synonymy is correct, however, according to the original descriptions ( Mahunka 1983; Woas 1986) of W. longiramosa and W. cervifer , and our supplementary description of W. cervifer , there are some differences between these species. For example, W. longiramosa has short (versus long in W. cervifer ) lateral prodorsal ridge and shorter (lm and lp not reaching lp and h 2, respectively versus reaching in W. cervifer ) dorsal notogastral setae. Also, one pair of short longitudinal interbothridial ridges not observable in W. longiramosa (versus developed in W. cervifer ). Therefore, I tentatively support the independence of the species status of W. longiramosa , however, the further study of the type material is necessary.

Acknowledgements

I cordially thank E.E. Lindquist for collecting oribatid mites from Guatemala, W. Knee for facilitating the loan of Guatemalan Acari material from the Canadian National Collection of Insects, Arachnids and Nematodes, Ottawa, Canada, and two anonymous reviewers for valuable comments.

References

Balogh, J. & Balogh, P. (1990) Oribatid mites of the Neotropical region. II. Akadémiai Kiadó press, Budapest, 333 p.

Balogh, J. & Balogh, P. (1992) The oribatid mite genera of the World. Vol. 1. Hungarian National Museum Press, Budapest, 263 p.

Balogh, J. & Balogh, P. (2002) Identification keys to the oribatid mites of the Extra-Holarctic regions. Vol. 1. Well-Press Publishing Limited, Miskolc, 453 p.

Balogh, J. & Mahunka, S. (1980) New data to the knowledge of the oribatid fauna of the Neogaea (Acari). V. Acta Zoologica Academiae Scientiarum Hungaricae, 26, 21–59.

Ermilov, S.G. (2024 a) New species of oribatid mites (Acari, Oribatida) of the genera Arcoppia (Oppiidae) and Cavernocepheus (Otocepheidae) from Guatemala. International Journal of Acarology, accepted. https://doi.org/10.1080/01647954.2024.2337204

Ermilov, S.G. (2024 b) Two new species of Amboroppia (Quintanoppia) (Acari, Oribatida, Oppiidae) from Guatemala. Acarologia, 64, 315–322. https://doi.org/10.24349/rba2-mlms

Ermilov, S.G. & Rybalov, L.B. (2022) Taxonomic contribution to the knowledge of the oribatid mite genus Arcoppia (Acari, Oribatida, Oppiidae). International Journal of Acarology, 48, 588–593. https://doi.org/10.1080/01647954.2022.2149854

Ermilov, S.G., Rybalov, L.B. & Hundama, T. (2014) Ethiopian oribatid mites (Acari, Oribatida): results of the Joint Russian-Ethiopian Biological Expedition (June 2013). Systematic and Applied Acarology, 19, 197–204. http://dx.doi.org/10.11158/saa.19.2.10

Hammer, M. (1977) Investigations on the oribatid fauna of North-West Pakistan. Det Kongelige Danske Videnskabernes Selskab Biologiske Skrifter, 21, 1–71.

Mahunka, S. (1983) Neue und interessante Milben aus dem Genfer Museum XLV. Oribatida Americana 6: Mexico II (Acari). Revue suisse de Zoologie, 90, 269–298.

Mahunka, S. & Mahunka-Papp, L. (2007). Taxonomical and faunistical studies on oribatids collected in Kenya (Acari: Oribatida) I. Acta Zoologica Academiae Scientiarum Hungaricae, 53, 51–74.

Norton, R.A. (1977) A review of F. Grandjean's system of leg chaetotaxy in the Oribatei (Acari) and its application to the family Damaeidae. In: Dindal, D.L. (Ed.), Biology of oribatid mites. SUNY College of Environmental Science and Forestry, Syracuse, pp. 33–61.

Norton, R.A. & Behan-Pelletier, V.M. (2009) Suborder Oribatida. Chapter 15. In: Krantz, G.W. & Walter, D.E. (Eds.), A Manual of Acarology. Texas Tech University Press, Lubbock, pp. 430– 564.

Subías, L.S. (2004) Listado sistemático, sinonímico y biogeográfico de los ácaros oribátidos (Acariformes, Oribatida) del mundo (1758–2002). Graellsia, 60 (número extraordinario), 3– 305.

Subías, L.S. (2022) Listado sistemático, sinonímico y biogeográfico de los ácaros oribátidos (Acariformes: Oribatida) del mundo (excepto fósiles). Monografías Electrónicas Sociedad Entomológica Aragonesa, 12, 1–538.

Subías, L.S. (2024) Listado sistemático, sinonímico y biogeográfico de los ácaros oribátidos (Acariformes: Oribatida) del mundo (excepto fósiles), 19 ª actualización, 1–545. Available from: http://bba.bioucm.es/cont/docs/RO_1.pdf (accessed January 2024).

Subías, L.S. & Balogh, P. (1989) Identification keys to the genera of Oppiidae Grandjean, 1951 (Acari: Oribatei). Acta Zoologica Hungarica, 35, 355–412.

Subías, L.S. & Shtanchaeva, U.Ya. (2023) Claves de familias, géneros y subgéneros de ácaros oribátidos del mundo (Acari, Oribatida). Monografías Electrónicas Sociedad Entomológica Aragonesa, 13, 1–290.

Woas, S. (1986) Beitrag zur Revision der Oppioidea sensu Balogh, 1972 (Acari, Oribatei). Andrias, 5, 21–224.

Figures

Figures 12–15. Wallworkoppia cervifer (Mahunka, 1983), adult (gnathosoma and legs omitted): 12—dorsal view; 13—ventral view; 14—right lateral view; 15—bothridial seta, lateral view. Scale bars 50 μm (12–14), 20 μm (15).

Figures 16–22. Wallworkoppia cervifer (Mahunka, 1983), adult: 16—subcapitulum, ventral view; 17—palp, right, antiaxial view; 18—chelicera, left, paraxial view; 19—leg I, right, antiaxial view; 20—leg II, right, antiaxial view; 21—leg III, left, antiaxial view; 22—leg IV, left, antiaxial view. Scale bars 10 μm (16–18), 50 μm (19–22).