Meromonakantha Sieg, 1986

Segadilha, Juliana Lopes, Serejo, Cristiana Silveira & Błażewicz, Magdalena, 2019, New species of Typhlotanaidae (Crustacea, Tanaidacea) from the Brazilian coast genera Hamatipeda, Meromonakantha and Paratyphlotanais, with description of Targaryenella gen. nov., Zootaxa 4661 (2), pp. 309-342 : 319

Genus Meromonakantha Sieg, 1986

LSID urn:lsid:zoobank.org:act:99DCF607-C12D-4F0C-B623-2CA63367C910

Diagnosis (modified after Larsen, 2005 and Błażewicz-Paszkowycz, 2007): Body almost completely cylindrical, well calcified; pereonites well separated, often swollen; pereonite-1 trapezoidal and pereonites 2–5 hexagonal; cephalothorax wider than pereonite-6; antennule with three articles, artice-1 robust (about twice L:W); article-3 with terminal spur; antenna with six articles, article-2 with long seta; mandible molar process broad, with distal margin nodulose; maxilla with 7–8 distal spines; maxilliped basis partly fused; endites not fused, with one or two large gustatory cusps on distal edge; cheliped attached via small sclerite; pereopods 1–3 with coxa, pereopod-1 carpus with setae only; propodus and dactylus combined shorter than propodus; pereopods 4–6 walking type, merus and carpus with simple or circumplumose spines; carpus without prickly tubercles; dactylus and unguis semifused or fused but not into a claw ( M. gilrowei ); pleopods present, endopod with inner subterminal seta present; exopod and endopod with setae on lateral and distal part (except exopod in M. nutae ), and gap between most proximal seta and others; uropod exopod and endopod slender, exopod with one or two articles, endopod with two articles (occasionally semi-fused).

Type species: Typhlotanais macrocephala Hansen, 1913 .

Species included: Meromonakantha gilrowei Larsen, 2005 ; M. (= Typhlotanais ) irregularis ( Hansen, 1913) ; M. (= Typhlotanais ) macrocephala ( Hansen, 1913) ; M. natatoris Błażewicz-Paszkowycz, 2007 ; M. nutae Błażewicz- Paszkowycz, 2007; M. (= Typhlotanais ) setosa ( Kudinova-Pasternak, 1966) ; M. mauri sp. nov. (see below).

Remarks. Genus Meromonakantha was erected to accommodate the typhlotanaid species that have a spine on the carpus of pereopods 2–3 (but occasionally also bristle-shaped) and to distinguish them from the other typhlotanaids that usually have only setae on that article ( Sieg, 1986). It is a distinct taxon that gathers typhlotanaids with a robustly calcified body cuticle, well-separated pereonites and pleonites, and with usually slender and elongate uropods. The species have a large cephalothorax whose length to width is usually greater than 1.4; however, a relatively slender cephalothorax is observed in M. natatoris , only 1.2 times L:W.

Błażewicz-Paszkowycz & Bamber (2012) have suggested that the species described by them as M. anarsios is only provisionally included in Meromonakantha , thus we remove this species from the genus and erect a new genus to accommodate the species (see below).