Morphological and molecular evidence for a new species of the genus Milnesium Doy`ere, 1840 (Tardigrada: Apochela) from south America

Author(s)

Brotto-Guidetti, Emiliana ; Morek, Witold ; Garraffoni, Andre R. S.

• Document type: Journal article
• Source: ZOOLOGISCHER ANZEIGER; v. 309, p. 11-pg., 2024-02-08.

Abstract

Tardigrades are aquatic microinvertebrates, that can be found from the poles to the tropical regions. However, knowledge about their diversity and distribution is still limited, especially regarding the Neotropical region. In addition, many species described in the past were considered cosmopolitan but new morphological, morphometric and especially molecular studies have demonstrated the existence of species complexes. The species Milnesium tardigradum Doye`re, 1840 is an example that highlights this issue. Many M. tardigradum records made in South America date from the time when this species was considered cosmopolitan and exhibiting large intraspecific variability. However, current revisions of the genus using modern techniques indicate that the M. tardigradum sensu stricto is most likely restricted to the Palaearctic region. In this contribution, we describe a new species, Milnesium iniquum sp. nov. from south-eastern Brazil, with additional records from Argentina and French Guiana, utilising integrative taxonomy framework. The new species is characterised by having smooth cuticle, presence of dorsal pseudoplates, adult claw configuration [3-3]-[3-3] and [2-2]-[2-2] in hatchlings (early positive CC change), with internal and anterior spurs larger than external and posterior spurs and by presence of short cuticular bars on legs IV. (AU)

• FAPESP's process: 14/23856-0 - Phylogenetic reconstruction of Gastrotricha based on molecular and morphological data
• Grantee: André Rinaldo Senna Garraffoni
• Support Opportunities: BIOTA-FAPESP Program - Young Investigators Grants
• FAPESP's process: 18/25213-0 - Integrative taxonomy: combining multiple approaches to better delimitation of South American species of the genus Milnesium Doyère 1840 (Tardigrada: Apochela: Milnesiidae)
• Grantee: Emiliana Brotto Guidetti
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 18/10313-0 - Build-up of scientific collections of marine invertebrates: strategies for biodiversity conservation
• Grantee: Antonia Cecília Zacagnini Amaral
• Support Opportunities: BIOTA-FAPESP Program - Thematic Grants