Two new species of Musellifer (Gastrotricha: Chaetonotida) from Florida and Tobago and the systematic placement of the genus within Paucitubulatina

Abstract

Two new species of marine Gastrotricha, Musellifer reichardti sp. nov. and Musellifer tridentatus sp. nov. (Chaetonotida: Paucitubulatina: Muselliferidae), are described from the Atlantic coast of Florida (USA) and the west coast of Tobago (Trinidad and Tobago), respectively. Both new species are peculiar in that they lack a muzzle bearing the mouth, which is a diagnostic character of the genus. They correspond well to the diagnosis of Musellifer in other morphological features, and genetic data from the 18S rDNA gene of M. reichardti sp. nov. further support the inclusion of the new species in the genus Musellifer. Musellifer reichardti sp. nov. is distinguished by the following combination of characters: blunt head with reduced muzzle; dorsal patches of naked cuticle bearing sensory cilia on either side of the head; ventral locomotory cilia restricted to the pharyngeal region; spined scales; caudal furca with naked adhesive tubes. The new species is a simultaneous hermaphrodite with posterior paired ovaries, paired testes located at mid-body length, and a posterior frontal organ. M. tridentatus sp. nov. is the first species within the genus exhibiting two types of dorsal/lateral scales: anteriormost dorsal and lateral trident-shaped scales and smooth strongly overlapping dorsal scales. The systematic placement of Musellifer within the Paucitubulatina is discussed and emended diagnoses are given for Muselliferidae and Musellifer.

Key words:

• Atlantic Ocean
• Gastrotricha
• meiofauna
• Muselliferidae
• Paucitubulatina
• taxonomy

Acknowledgements

The authors thank Cheryl Thacker and Daniel Gouge for their wonderful assistance with SCUBA collections during the Tobago expedition. The authors also thank the staff at the Smithsonian Marine Station in Fort Pierce, Florida and the staff at the Manta Lodge, Speyside, Tobago for their help during collections and their hospitality. The Swedish Taxonomy Initiative is also acknowledged.

Funding

This is Smithsonian Marine Station contribution number 884. This material is based upon work supported by the National Science Foundation under Grant No. DEB 0918499.

Editorial responsibility: Tomas Cedhagen

Additional information

Funding

Funding: This is Smithsonian Marine Station contribution number 884. This material is based upon work supported by the National Science Foundation under Grant No. DEB 0918499.