Abstract
Megalothorax Willem, 1900 is a genus of Neelidae (Collembola) with worldwide distribution. Three new species are described here: Megalothorax anterolenis sp. nov. (Patagonia, Chile), Megalothorax tasmanterolenis sp. nov. (Tasmania, Australia) and Megalothorax zealanterolenis sp. nov. (the South Island, New Zealand). New descriptive elements are also provided for Megalothorax rubidus. Two of the new species were sequenced (COI, 16S rDNA, 28S rDNA). Within the genus, the three new species form a new group of species characterised by the absence of secondary granulation dorsally on the head and the thorax, a reduced chaetotaxy of the basomedian field of labium, a bifurcate hair on the maxillary outer lobe and an enlarged S-chaeta (Sa2) on Ant. IV. The molecular based phylogeny further supports the sistership of the two sequenced species. The possible Gondwanan origin of the new group is discussed. Elements of discussion are also provided regarding the possible function of the incomplete coverage of secondary granulation. Finally, an open interactive identification key for the Megalothorax species of the world is introduced.
References
Bretfeld, G. & Griegel, A. (1999) Description of a new Neelidae genus and species and of new specimens of Sminthurides annulicornis Axelson 1905 from Poland (Insecta, Collembola, Neelidae). Senckenbergiana Biologica, 79 (2), 211–223.
Caroli, E. (1912) Collembola. 1. Su di un nuovo genere di Neelidae. Annuario Musee Zool. N.S. Supplemento 1 Fauna delgi Astroni, 4, 1–5.
Dallai, R. (1979) Investigations on Collembola XXIV. On the systematic of Neelidae with redescription of Neelides folsomi Caroli. Animalia, 6 (1–3), 271–281.
Deharveng, L. (1978) Collemboles cavernicoles. 1. Grottes de l'Aguzou (France: Aude). Bulletin de la Société d'Histoire naturelle de Toulouse, 114 (3–4), 393–403.
Denis, J.R. (1948) Collemboles d’Indochine. Notes d'Entomologie Chinoise, 12 (17), 183–311.
Dunger, W., Schulz, H.-J. & Zimdars, B. (2002) Colonization behaviour of Collembola under different conditions of dispersal. Pedobiologia, 46 (3–4), 316–327. https://doi.org/10.1078/0031-4056-00139
Eagles, G. & Jokat, W. (2014) Tectonic reconstructions for paleobathymetry in Drake Passage. Tectonophysics, 611, 28–50. https://doi.org/10.1016/j.tecto.2013.11.021
Folsom, J.W. (1896) Neelus murinus, representing a new thysanuran family. Psyche, 7, 391–409.
Freeman, J.A. (1952) Occurrence Of Collembola In The Air. Proceedings of the Royal Entomological Society of London. Series A, General Entomology, 27 (1–3), 28. https://doi.org/10.1111/j.1365-3032.1952.tb00142.x
Gundersen, H., Leinaas, H.P. & Thaulow, C. (2014) Surface Structure and Wetting Characteristics of Collembola Cuticles. PLoS ONE, 9 (2), 1–11. https://doi.org/10.1371/journal.pone.0086783
Hawes, T.C., Worland, M.R., Bale, J.S. & Convey, P. (2007) Rafting in Antarctic Collembola. Journal of Zoology, 274 (1), 44–50. https://doi.org/10.1111/j.1469-7998.2007.00355.x
Kalyaanamoorthy, S., Minh, B.Q., Wong, T.K.F., von Haeseler, A. & Jermiin, L.S. (2017) ModelFinder: fast model selection for accurate phylogenetic estimates. Nature Methods, 14 (6), 587–589. https://doi.org/10.1038/nmeth.4285
Katoh, K. & Standley, D.M. (2013) MAFFT Multiple Sequence Alignment Software Version 7: Improvements in Performance and Usability. Molecular Biology and Evolution, 30(4), 772–780. https://doi.org/10.1093/molbev/mst010
Laird, M. & Bradshaw, J. (2004) The Break-up of a Long-term Relationship: the Cretaceous Separation of New Zealand from Gondwana. Gondwana Research, 7 (1), 273–286. https://doi.org/10.1016/s1342-937x(05)70325-7
Moore, P.D. (2002) Springboards for springtails. Nature, 418 (6896), 381–381. https://doi.org/10.1038/418381a
Mortimer, N., van den Bogaard, P., Hoernle, K., Timm, C., Gans, P.B., Werner, R. & Riefstahl, F. (2019) Late Cretaceous oceanic plate reorganization and the breakup of Zealandia and Gondwan. Gondwana Research, 65, 31–42. https://doi.org/10.1016/j.gr.2018.07.010
Nguyen, L.-T., Schmidt, H.A., von Haeseler, A. & Minh, B.Q. (2014) IQ-TREE: A Fast and Effective Stochastic Algorithm for Estimating Maximum-Likelihood Phylogenies. Molecular Biology and Evolution, 32 (1), 268–274. https://doi.org/10.1093/molbev/msu300
Nickerl, J., Helbig, R., Schulz, H.-J., Werner, C. & Neinhuis, C. (2012) Diversity and potential correlations to the function of Collembola cuticle structures. Zoomorphology,, 132 (2), 183–195. https://doi.org/10.1007/s00435-012-0181-0
Panina, K., Babenko, A. & Potapov, M. (2022) Two new nosed species of the genus Megalothorax (Collembola: Neelidae) from Russia. Zootaxa, 5188 (4), 383–395. https://doi.org/10.11646/zootaxa.5188.4.6
Papáč, V. & Kováč, Ľ. (2013) Four new troglobiotic species of the genus Megalothorax Willem, 1900 (Collembola: Neelipleona) from the Carpathian Mountains (Slovakia, Romania). Zootaxa, 3737 (5), 545–575. https://doi.org/10.11646/zootaxa.3737.5.3
Papáč, V., Raschmanová, N. & Kováč, Ľ. (2019) New species of the genus Megalothorax Willem, 1900 (Collembola: Neelipleona) from a superficial subterranean habitat at Dobšinská Ice Cave, Slovakia. Zootaxa, 4648 (1), 165–177. https://doi.org/10.11646/zootaxa.4648.1.9
Robin, N., D’Haese, C. & Barden, P. (2019) Fossil amber reveals springtails’ longstanding dispersal by social insects. BMC Evolutionary Biology, 19 (213), 1–12. https://doi.org/10.1186/s12862-019-1529-6
Salmon, J.T. (1944) New genera, species, and records of New Zealand Collembola, and a discussion of Entomobrya atrocincta Schött. Records of the Dominion Museum, 1, 123–182.
Salmon, J.T. (1946) Collembola – Symphypleona from the Homer district. Dominion Museum Records in Entomology, 1 (4), 27–61.
Scher, H.D., Whittaker, J.M., Williams, S.E., Latimer, J.C., Kordesch, W.E.C. & Delaney, M.L. (2015) Onset of Antarctic Circumpolar Current 30 million years ago as Tasmanian Gateway aligned with westerlies. Nature, 523 (7562), 580–583. https://doi.org/10.1038/nature14598
Schneider, C. (2014) Systématique et phylogénie des Neelipleona (Collemboles). Unpublished doctoral dissertation, Muséum national d’histoire naturelle, Paris, 397 pp.
Schneider, C. (2017) Morphological review of the order Neelipleona (Collembola) through the redescription of the type species of Acanthoneelidus, Neelides and Neelus. Zootaxa, 4308 (1), 1–94. https://doi.org/10.11646/zootaxa.4308.1.1
Schneider, C. (2022) Open key of the Megalothorax species of the world (Collembola: Neelidae) (v1.0.0). Zenodo. [published online] https://doi.org/10.5281/zenodo.7341417
Schneider, C. & Deharveng, L. (2017) First record of the genus Spinaethorax Papáč & Palacios-Vargas, 2016 (Collembola, Neelipleona, Neelidae) in Asia, with a new species from a Vietnamese cave. European Journal of Taxonomy, 363, 1–20. https://doi.org/10.5852/ejt.2017.363
Schneider, C. & D’Haese, C.A. (2013) Morphological and molecular insights on Megalothorax: the largest Neelipleona genus revisited (Collembola). Invertebrate Systematics, 27 (3), 317–364. https://doi.org/10.1071/IS13002
Schneider, C., Porco, D. & Deharveng, L. (2016) Two new Megalothorax species of the minimus group (Collembola, Neelidae). ZooKeys, 554, 37–68. https://doi.org/10.3897/zookeys.554.6069
Schneider, C., Zon, S.D. & D’Haese, C.A. (2018) Megalothorax laevis (Neelipleona, Neelidae): Account of a neglected springtail widely distributed in the intertropical zone. International Journal of Tropical Insect Science, 38 (3), 168–191. https://doi.org/10.1017/S1742758418000024
Vignes-Lebbe, R., Chesselet, P., Diep Thi, M.H., Rakotoarisoa, N.R., Blackmore, S. & Riera, B. (2016) Xper3: new tools for collaborating, training and transmitting knowledge on botanical phenotypes. In: Rakotoarisoa ,N., Loizeau, P. & Palese, R. (Eds.), Botanists of the twenty first century: roles, challenges and opportunities. UNESCO, Paris, pp. 228–239.
Willem, V. (1900) Un type nouveaux des Smynthuridae: Megalothorax. Annales de la Société Entomologique de Belgique, 44, 7–10.