Hypotrabala obscura, Takano & László, 2024

Takano, Hitoshi & László, Gyula M., 2024, Descriptions of new Hypotrabala Holland, 1893 (Lepidoptera: Lasiocampidae: Lasiocampinae: Selenepherini) in the collections of the African Natural History Research Trust, with notes on allied genera and the description of a new genus, Ecologica Montenegrina 72, pp. 19-63 : 48-63

Hypotrabala obscura sp. n.

https://zoobank.org/ urn:lsid:zoobank.org:act:7BC257AD-9F90-4600-A3FB-24BAA861F80D

( Figs 56–57 , 72 )

Holotype ♂ ( ANHRT):

“ GABON 10m / Nyonié (Lowland forest) / 0°2’22”S, 9°20’25”E / 23-28.viii.2019 MV Light Trap / Albert, J-L., Aristophanous, M., / Bie Mba, J., Dérozier V., / Moretto, P. Leg. / ANHRT :2019.17 //

ANHRTUK / 00172019 // Gen. slide No. / LG 6331 ♂ / prep. by Gy. M. Laszlo [black border; partially handwritten]”

Paratypes (3♂♂):

GABON: same data as holotype (3♂♂ ANHRT) .

Description.

Forewing length: holotype: 22 mm; paratypes: 21–22 mm.

Upperside. Ground colour of head, thorax and forewings chocolatey-brown; abdomen and hindwings greyish-khaki. Antenna bipectinate, brown. Forewing pointed at apex, outer margin gently arcuate; distally paler. Antemedial fascia orangey-brown, bilineate, crenulate, indistinct. Discal spot reniform silvery-white, the width of the cell and ringed in black. Postmedial fascia indicated in one of the paratypes with indistinct orangey-brown spots. Fringe dark greyish-brown. Hindwing outer margin arcuate, almost angled at vein CuA2; darker towards the margins. Costa with greyish-brown scaling. Fringe dark greyish-brown.

Underside. Ground colour as upperside. Forewing paler basally. Discal spot pale brown. Hindwing costa dark greyish-brown.

Male genitalia. Socius relatively short, ca. one-fifth the length of valve, arms gradually tapered to pointed apex, arising far apart from each other, diverging at ca. 120° angle. Tegumen moderately long and broad, inner margin slightly arcuate. Valve very long, narrow basally, tapered subapically to pointed tip, gently curved in posterior third. Juxta with long, robust, rounded posteromedial process. Vinculum narrow ribbon-like medially, with short, rounded-triangular lateral plates. Phallus very short, coecum penis large, as long as sclerotised part of phallus, membranous sack-like, loosely attached to juxta; sclerotised section of phallus gradually tapered, curved dorsad, apically pointed. Vesica basally inflated, relatively large, somewhat ovoid, finely scobinate, anteriorly with two long and thick, densely serrate almost straight longitudinal plates consisting of fine teeth, forming a V-shape; posterior section of inflated vesica with a very small, narrow finely dentate diagonal plate. Sclerotised plate of eighth sternite anteriorly slightly concave with relatively long and thick anterolateral apodemes, posteriorly dilated to two short plates with gently sinuous margin possessing two short posterior sclerotisations divided by shallow medial depression.

Diagnosis. Hypotrabala obscura is a unique species within the genus with uniformly dark brown wings lacking orange or yellow patterning. The male genitalia is most similar to H. pruinosa but in the latter, the socii are longer, the posteromedial process of the juxta is shorter, the valves are longer, and the serrate plates of the vesica are shorter. It is also worth noting that the coecum penis of H. obscura is loosely connected to the juxta which enables the phallus to be detached easily from the capsule.

DNA divergences. The new species has been assigned the BIN BOLD:AEH6352. Intraspecific PWDs were 0.0% (n=3) and differed by 1.9% from the nearest sample ( H. tamsi ).

Derivatio nominis. The new species derives its name from its uniquely dark and uniform phenotype.

Discussion and conclusions

Recently-collected material housed in the collections of the African Natural History Research Trust has enabled a thorough review of Hypotrabala and its allied genera which are in general poorly represented in museum collections (current observation). A hidden diversity of Hypotrabala species has been uncovered as a result of taxonomic analyses integrating morphological and molecular traits. The generic boundary has been delimited with Epitrabala now considered a junior synonym of Hypotrabala . Furthermore, two taxa have been transferred to an allied genus Leptometa , one taxon confidently removed from Hypotrabala and considered incertae sedis, and a new genus Megatrabala established for the distinctive taxon regalis . Hypotrabala now contains 28 species, more than tripling the number of species previously known.

The results of the phylogenetic analyses were largely congruent with the species concepts based on morphology with the exception of one poorly resolved clade containing polyphyletic and paraphyletic taxa. This outcome only highlights the dangers of relying solely upon barcode data without due consideration of morphology. There is little doubt that operational taxonomic units such as BINs are of great utility and are often indicative of putative taxa but an over-reliance on clustering algorithms without additional morphological and informed biogeographical evidence can lead to inaccurate delimitations of taxa. The intraspecific PWDs of two morphologically distinct and delimitable taxa attracted particular attention: samples of H. tamsi (0.0–4.0%) and H. horridula (0.2–4.1%) were each recovered in at least two BINs with large divergences; although the two populations of H. tamsi are disjunct, there is no geographical circumscription in the H. horridula specimens (samples from both BINs being found sympatrically) and most critically in both taxa, the genital morphology is constant. Some recent descriptions of Afrotropical Lasiocampidae taxa (e.g., Prozorov et al. 2024) have been based primarily on barcode divergences, and such ‘barcode- gap’ approaches can be particularly misleading in this family as the results of the current analyses as well as other genera (Takano, in prep.) have shown.

Records indicate that Hypotrabala species are widely distributed throughout sub-Saharan Africa from Sierra Leone in the west to Kenya in the east and Mozambique in the south, inhabiting both open woodland and tropical rainforest habitats. Those taxa associated with the former (e.g., H. horridula / H. argenteoguttata ) appear to be more widely distributed whereas there appears to be a greater diversity in the latter, with no cross-over between the West African and Central African forests. Even from a relatively small dataset such as this, the well-known pattern of species divergences across the two forest blocks (e.g., Takano 2021) may explain the observed differences in the species assemblages but more material needs to be examined to support this hypothesis.

Despite their large size and beautiful colouration, the true diversity of the Afrotropical Lasiocampid fauna remains unclear; but if the results of this present generic review are any indication, a wealth of taxa still await description.

Acknowledgements

We extend our grateful thanks to the following collaborative partners and their personnel for the diverse administrative and technical assistance provided during ANHRT’s fieldwork: Ministère de l’Enseignement Supérieur et de la Recherche Scientifique, Office Ivoirien des Parcs et Réserves ( OIPR), and Société de Développement des Forêts (SODEFOR) in Ivory Coast ; Centre National de la Recherche Scientifique (CENAREST), Rougier Gabon , and Université des Sciences et Techniques de Masuku ( USTM) in Gabon ; Centre de Gestion de l’Environnement du Nimba et du Simandou, Centre Forestiére de N’zérékoré, and Guinée Ecologie in Guinea; Forestry Department Authority, Society for the Conservation of Nature , and Wild Chimpanzee Foundation in Liberia ; Administração Nacional das Areas de Conservação , and Museu de História Natural de Maputo in Mozambique ; Direction de la Faune et des aires protégées ( DFAP), Institut National de Recherche en Sciences Exactes et Naturelles ( IRSEN), Ministère de la Recherche scientifique et de la l’Innovation Technologique, Université Marien Ngouabi, and Wildlife Conservation Society ( WCS) in Republic of Congo ; Ministry of Agriculture , Fisheries and Food Security, and Njala University in Sierra Leone ; Ministre de l’Environnement et des ressources forestières du Togo , and Université de Lomé in Togo ; Department of National Parks and Wildlife – Zambia Wildlife Authority ( ZAWA), and Livingstone Museum in Zambia . We thank Alessandro Giusti ( NHMUK) for facilitating access to study the type material under his care, Geoff Martin ( NHMUK) for helpful discussions regarding the NHMUK genitalia slides and vials, and Danielle Czerkaszyn , Librarian and Archivist , Oxford University Museum of Natural History for her kind assistance in sourcing literature. The images of the holotypes in NHMUK are reproduced with permission from the Trustees of the Natural History Museum, London and made available under Creative Commons license 4.0 (https://creativecommons.org/licenses/by/4.0/). The authors declare that to the best of their knowledge, they conform to the national regulations and meet with the conditions and requirements of International Conventions concerning collecting/export and handling of the specimens presented in this article .

References

Aurivillius, C. (1927) Lasiocampidae. In: Seitz, A. (Ed.) Die Gross-Schmetterlinge der Erde. Eine Systematische Bearbeitung der bis jetzt bekannten Gross-Schmetterlinge. Die Afrikanischen Spinner und Schwärmer. Verlag des Seitzschen Werkes, Alfred Kernen, Stuttgart, pp. 205–281. [In German]

Basquin, P. (2023) Découvrons les Lasiocampides africains. Saturnafrica, 32, 37–47. [In French]

Berio, E. (1937) Eteroceri africani apparentemente nuovi. Annali del Museo Civico di Storia Naturale Giacomo Doria, 59, 370–393. [In Italian]

Collier, W.A. (1936) Lasiocampidae. In: Strand, E. (Ed.) Lepidopterorum Catalogus, pars. 73. Dr. W.

Junk, ‘s- Gravenhage [=The Hague], pp. 1–484. [In German]

Edler, D., Klein, J., Antonelli, A. & Silvestro, D. (2021) raxmlGUI 2.0: A graphical interface and toolkit for phylogenetic analyses using RAxML. Methods in Ecology and Evolution, 12 (2), 373–377.

https://doi.org/10.1111/2041-210X.13512

Fletcher, D.S. & Bradley, J.D. (1981) Obituaries: W.H.T. Tams 1891 –1980. Proceedings and Transactions of the British Entomological and Natural History Society, 14, 34–36.

Hebert, P.D.N., Braukmann, T.W.A., Prosser, S.W.J., Ratnasingham, S., deWaard, J.R., Ivanova, N.V., Janzen, D.H., Hallwachs, W., Naik, S., Sones, J.E. & Zakharov, E.V. (2018) A Sequel to Sanger: amplicon sequencing that scales. BMC Genomics, 19, 219.

https://doi.org/10.1186/s12864-018-4611-3

Hering, E.M. (1932) Neue Heteroceren aus Afrika. Revue de Zoologie et Botanique Africaines, 22 (1), 102–117. [In German]

Joannou, J. & Kühne, L. (2008) Family Lasiocampidae, Eggar Moths (Bombycoidea). In: Kühne, L. (Ed.) Butterflies and moth diversity of the Kakamega forest (Kenya). Self-published, pp. 125– 134.

Kimura, M. (1980) A simple method for estimating evolutionary rate of base substitutions through comparative studies of nucleotide sequences. Journal of Molecular Evolution, 16, 111–120.

https://doi.org/ 10.1007/BF01731581

Kumar, S., Stecher, G., Li, M., Knyaz, C. & Tamura, K. (2018) MEGA X: Molecular Evolutionary Genetics Analysis across computing platforms. Molecular Biology and Evolution, 35, 1547– 1549. https://doi.org/ 10.1093/molbev/msy096

Lafontaine, J.D. & Mikkola, K. (1987) Las-och-nyckel systemen i de inre genitalierna av Noctuidae (Lepidoptera) som taksonomiska kaennetecken. [Lock-and-key systems in the inner genitalia of Noctuidae (Lepidoptera) as a taxonomic character.] Entomologiske Meddelelser, 55, 161–167. [In Swedish]

Pinhey, E.C.G. (1975) Moths of Southern Africa. Tafelberg Publishers, Cape Town, iv, 273 pp.

Prozorov, A.M., Prozorova, T.A., Yakovlev, R.V., Volkova, J.S., Saldaitis, A., Sulak, H., Revay, E.E. & Müller, G.C. (2024) Description of two new species of Dinometa from East Africa with remarks on D. maputuana (Lepidoptera, Lasiocampidae, Lasiocampinae). Zootaxa, 5397 (4), 486–496. https://doi.org/10.11646/zootaxa.5397.4.2

Ratnasingham, S. & Hebert, P.D.N. (2007) BOLD: The Barcode of Life Data System (http://www.barcodinglife.org). Molecular Ecology Notes, 7 (3), 355–364.

https://doi.org/10.1111/j.1471-8286.2007.01678.x

Ronquist, F., Teslenko, M., Van Der Mark, P., Ayres, D.L., Darling, A., Höhna, S., Larget, B., Liu, L., Suchard, M.A. & Huelsenbeck, J.P. (2012) MrBayes 3.2: efficient Bayesian phylogenetic inference and model choice across a large model space. Systematic Biology, 61 (3), 539–542.

https://doi.org/10.1093/sysbio/sys029

Takano, H. (2021) Two new species of Polyptychus Hübner, [1819] (Lepidoptera: Sphingidae: Smerinthinae) from West Africa. Ecologica Montenegrina, 47, 1–8.

https://doi.org/10.37828/em.2021.47.1

Takano, H. & László, G.M. (2022) A new species of Cryptopacha Prozorov & Zolotuhin, 2012 (Lasiocampidae: Lasiocampinae) from West Africa. Bonn zoological Journal, 71 (1), 19–22.

https://doi.org/10.20363/BZB-2022.71.1.019

Tams, W.H.T. (1925) LXX – African Lasiocampidae: Notes and new species. Annals and Magazine of Natural History, (9) 16, 552–561.

Tams, W.H.T. (1953) Two new representatives of the genus Hypotrabala (Lepidoptera: Lasiocampidae) from the Belgian Congo. Bulletin of the British Museum (Natural History): Entomology, 3 (2), 74–75.

Vári, L., Kroon, D.M. & Krüger, M. (2002) Classification and Checklist of the Species of Lepidoptera Recorded in Southern Africa. Simple Solutions, Chatswood, 384 pp.

Zolotuhin, V.V. & Prozorov, A.M. (2010) A review of the genera Opisthodontia Aurivillius, 1895, and Stenophatna Aurivillius, 1909, with erection of 8 new genera and descriptions of 37 new species and 2 new subspecies (Lepidoptera, Lasiocampidae). Atalanta, 41 (3/ 4), 397–460.

Zolotuhin, V.V., Efimov, R.V., Anikin, V.V., Demin, A.G. & Knushevitskaya, M.V. (2012) Changes in the Suprageneric Classification of Lasiocampidae (Lepidoptera) Based on the Nucleotide Sequence of Gene EF-1α. Entomological Review, 92 (5), 531–547.

https://doi.org/10.1134/S0013873812050065

Figures

Figures 50–59. Hypotrabala species: 50. H. pruinosa sp. n., holotype ♂. 51. Id., paratype ♂. 52. H. indefinita sp. n., holotype ♂. 53. Id., paratype ♂. 54. H. pallens sp. n., holotype ♂. 55. Id., paratype ♂. 56. H. obscura sp. n., holotype ♂. 57. Id., paratype ♂. 58. H. dollmani Tams, 1925, holotype ♂ [NHMUK 010292293]. 59. Id., paratype ♂ [NHMUK 010292327].

Figures 72–77. Male genitalia of Hypotrabala species, a: clasping apparatus, b: lateral view of phallus, c: eighth sternite, d: dorsal view of phallus (a, b, c to scale, d magnified). 72. H. obscura sp. n., holotype [LG 6331]. 73. H. giustii sp. n., holotype [LG 6295]. 74. Id., paratype [LG 6296]. 75. H. argenteoguttata (Aurivillius, 1909), Mozambique [LG 6322]. 76. H. tamsi sp. n., holotype [LG 6291]. 77. Id., paratype, Cameroon [LG 6290].