Abstract
The knowledge of the diversity and distribution of tardigrades on Madagascar is rather poor. To date, only 13 tardigrade taxa have been reported from this region (including one Milnesium species). We examined 46 specimens belonging to two new-to-science species of the genus Milnesium described herein using an integrative approach, including classical morphology and molecular marker (COI, ITS-2 and 28S rRNA) analysis. The species were found in two moss and lichen samples collected in the Ivohibory forest in Fianarantsoa Province. Milnesium matheusisp. nov., with claw configuration [3-3]–[3-3] and rather wide buccal tube, morphologically is most similar to: Mil. beatae Roszkowska, Ostrowska & Kaczmarek, 2015, Mil. bohleberi Bartels, Nelson, Kaczmarek & Michalczyk, 2014, Mil. eurystomum Maucci, 1991, Mil. shilohae Meyer, 2015 and Mil. tumanovi Pilato, Sabella & Lisi, 2016; however, it differs from these by morphometric characteristics. Milnesium wrightaesp. nov., by the presence of four points on secondary branches of claws IV, is most similar to Mil. quadrifidum Nederström, 1919. However, Mil. wrightaesp. nov. differs from Mil. quadrifidum by claw configuration ([4-4]–[4-4] in Mil. quadrifidum vs. [3-3]–[4-4] in Mil. wrightaesp. nov.), but also by the position of the fourth points on secondary branches of claws IV, which are located near the base of the claw in the new species and near the top of the claw in Mil. quadrifidum. Genotypic analysis showed that Mil. matheusisp. nov. is most similar to Milnesium sp. (28S rRNA), Mil. variefidum (COI) and Mil. t. tardigradum (ITS-2) while Mil. wrightaesp. nov. is most similar to Milnesium sp. (28S rRNA), Mil. variefidum (COI) and Mil. matheusi (ITS-2). Five Milnesium taxa are recorded from the African region, including the two new species from Madagascar reported in this study.
Highlights
Madagascar stretches from ~12° to ~26°S latitude on the Indian Ocean, more than 400 km east of Africa
Mil. wrightae sp. nov. differs from Mil. quadrifidum by claw configuration ([4-4]–[4-4] in Mil. quadrifidum vs. [3-3]–[4-4] in Mil. wrightae sp. nov.), and by the position of the fourth points on secondary branches of claws IV, which are located near the base of the claw in the new species and near the top of the claw in Mil. quadrifidum
Genotypic analysis showed that Mil. matheusi sp. nov. is most similar to Milnesium sp. (28S rRNA), Mil. variefidum (COI) and Mil. t. tardigradum (ITS-2) while Mil. wrightae sp. nov. is most similar to Milnesium sp. (28S rRNA), Mil. variefidum (COI) and Mil. matheusi (ITS-2)
Summary
Madagascar stretches from ~12° to ~26°S latitude on the Indian Ocean, more than 400 km east of Africa. Madagascar has a tropical climate with two main climatic and biogeographic zones characterised by a substantially different vegetation cover, i.e., evergreen humid forests and deciduous forests divided by a mountain range that extends from north to south in eastern-central Madagascar (Du Puy and Moat 1996) Both zones are divided into several regions, each of which has distinctive climatic features and a set of unique habitats. The Ivohibory forest – which is a humid rainforest with some patches of grassy clearings – covers an area of approximately 1400 ha with an elevation gradient stretching from 900 to 1500 m asl, surrounded by human-created savannah, with a few lasting micro-patches of dry forest It is situated on quartzite deposits, which is unique for this region (Wright and Houlihan 2017). This paper describes two new species from Madagascar using integrative taxonomy
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