Nototanaidae, Sieg, 1976

Błażewicz-Paszkowycz, Magdalena, 2007, Figure 6. Typhlotanais Compactus, Female A In Family Nototanaidae Sieg, 1976 And Typhlotanaidae Sieg, 1984, Zootaxa 1598, pp. 1-141 : 9-10

Family: Nototanaidae sensu lato

Diagnosis (modified after Larsen &Wilson, 2002). Female: Antennule three-articled. Antenna six-articled. Cheliped with side piece. Pereopods 4-6 of the walking type. Marsupium formed from four pairs of oostegites.

Male (where known): terminal (non-feeding) type.

Genera included: Bathytanaissus ; Nesotanais ; Nototanais ; Protanaissus ; Tanaissus ; Paratyphlotanais , and Meromonakantha .

Remarks: Undoubtedly the Nototanaidae is a polyphyletic taxon and perhaps two clear phylogenetic lines can be observed. The monotypic Teleotanais gerlachi Lang, 1956 , with a four-articled antennule, has been probably wrongly assigned to the family and, following the family definition, cannot be included. The first phylogenetic line embraces nototanaid genera with the cheliped attached via a sclerite and with a bifid right mandible incisor with crenulated upper margin ( Bathytanaissus , Nesotanais , Nototanais, Protanaissus, Tanaissus ). Noreworthy if that three of those five genera have ‘terminal males’, with reduced mouthparts and strongly modified chelipeds (adult males Bathytanaissus and Protanaissus are currently unknown).

The ‘typhlotanaid-like’ Paratyphlotanais and Meromonakantha may form another phylogenetic line, being species with a cheliped lacking a sclerite and with a simple incisor. There is scarce information about males within those genera; Bird (2004a) suggested that they may be morphologically similar to the females and often overlooked.

The most evident characters distinguishing true Nototanaidae (first phylogenetic line) from true Typhlotanaidae is the attachment of the cheliped (via a sclerite in the Nototanaidae and without a sclerite in the Typhlotanaidae ) and the walking morphology of the last three pair of pereopods in the Nototanaidae versus the clinging type in the Typhlotanaidae . Two further differences between these families regard the structure of the mouthparts. The upper part of the mandible incisor is bifid and serrated in the Nototanaidae , but in the Typhlotanaidae it is simple and smooth. The other character applies to the distal part of maxillule endite: in the Nototanaidae this appendage is bent almost at a right angle distally and usually its outer margin is covered by dense setae, but in the Typhlotanaidae it is almost straight and naked. The shape and setation of the maxillule and associated mouthparts, although difficult for discrimination or observation (the maxilla is often damaged or lost during dissection), are probably important features which should be considered more when attempting to reconstruct tanaidomorph phylogeny.