Scottolana tama, Gómez & Yáñez-Rivera & García-Vázquez & Armenteros, 2024

Gómez, Samuel, Yáñez-Rivera, Beatriz, García-Vázquez, Leonardo & Armenteros, Maickel, 2024, On some new species of Canuelloida Khodami, Vaun MacArthur, Blanco-Bercial & Martinez Arbizu, 2017 (Crustacea: Copepoda) from a shallow coastal lagoon in north-western Mexico, Zootaxa 5555 (4), pp. 497-534 : 529

Justification of S. tama sp. nov.

Fiers (1984) described a new species of Scottolana , S. antillensis , from Jamaica. This species was, at the time, the only one in which the female caudal seta II is modified into a strong blunt short spine. Fiers (1984) believed that S. antillensis resembled most S. bulbifera , but differed in the free P1-bearing somite [fused to cephalosome as shown in ( Chislenko 1971)], in armature formula of P4EXP3 [with four setae in S. antillensis , but with five elements in Chislenko’s (1971) S. bulbifera ], and shape of the spines of P3ENP [outer spine on P3EXP1 elongate, and inner seta on P3ENP1 relatively shorter in Chislenko’s (1971) S. bulbifera ]. Mu & Huys (2004) provided the full redescription of S. bulbifera upon material from the Bohai Sea. They showed that the P1-bearing somite is not fused to the cephalosome, and that the outer spine on P3EXP1 is visibly longer than the other outer spines of that ramus, that the inner element on P3ENP1 is relatively shorter than in S. antillensis and spiniform, and that the P4EXP3 possesses four elements instead of five as in Chislenko (1971) who might have confused the distal inner outgrowth of P4EXP3 with a spine. Scottolana tama sp. nov. is clearly closely related to S. antillensis with which conforms a Neotropical monophyletic group defined by the (aut)apomorphic caudal seta II modified into a strong blunt short spine. These two species can be separated by i) the presence of a small setule-like structure on the modified seta II in the female of S. tama sp. nov. probably homologous to the whip-like distal part of caudal seta II of the bulbosa - group [ Fiers (1984) inspected two females and did not observe such structure]; ii) female antennule with second to fifth segments imperfectly separated in S. tama sp. nov., but distinctly separated in S. antillensis [ Fiers (1984) stated that the female antennule of S. antillensis is similar to that of S. dissimilis ]; iii) antennary exopod eight-segmented in S. tama sp. nov. with one seta on first and second segments, but seven-segmented in S. antillensis with two setae on first segment [this might be an observational error since the second segment is sometimes concealed by the first segment giving the false impression of a single segment with two setae; also, the antennary exopod of Scottolana was diagnosed with eight–nine setae in Mu & Huys (2004)]; iv) mandibular exopod with two setae on the first segment in S. tama sp. nov., but with one seta in S. antillensis , and second endopodal segment with eight setae in S. tama sp. nov., but with nine setae in S. antillensis ; v) maxillulary exopod with eleven setae in S. tama sp. nov., but with ten setae in S. antillensis , vi) maxillary endopod two-segmented in S. tama sp. nov., but one-segmented in S. antillensis ; vii) the syncoxa of the maxilliped possesses nine setae (one praecoxal, eight coxal), the basis has two and the endopod 11 setae in S. tama sp. nov., but the syncoxa possesses ten elements (one praecoxal, nine coxal), basis has three and endopod ten setae in S. antillensis [ Fiers (1984) interpreted the praecoxa and coxa of the maxilliped as separate segments of which the praecoxa is unarmed; the division between the praecoxa and coxa in Fiers’ (1984) figure 2a is reinterpreted here as an integumental fold, thus being the praecoxa and coxa fused, with one praecoxal and nine coxal elements; the distalmost basal seta in Fiers’ (1984) figure 2a is reinterpreted here as the innermost proximal endopodal seta, and therefore, the endopod possesses 11 setae instead]; viii) male P6 with one distal seta in S. tama sp. nov., but unarmed in S. antillensis [however Fiers (1984), only found and inspected one male whose P6 seems to have the inner cuticle interrupted [see Fiers’ (1984) figure 3g], probably indicating the place where an armature element was inserted; the unarmed condition of the male P6 of S. antillensis still needs confirmation].