Bulbamphiascus Lang, 1944

Gómez, Samuel, Corgosinho, Paulo Henrique Costa & Rivera-Sánchez, Karen I., 2021, Proposal of new genera and species of the subfamily Diosaccinae (Copepoda: Harpacticoida: Miraciidae), European Journal of Taxonomy 759 (1), pp. 1-62 : 39-41

Bulbamphiascus Lang, 1944

Type species

Canthocamptus imus Brady, 1872 , by original designation.

Other species

Bulbamphiascus denticulatus ( Thompson, 1893) , B. incus Gee, 2005 , B. plumosus Mu & Gee, 2000 and B. scilloniensis Gee, 2005 .

Species incertae sedis

Bulbamphiascus chappuisi Rouch, 1962 .

Amended diagnosis

Miraciidae : Diosaccinae . Body fusiform. Rostrum not fused to cephalothorax, triangular, elongate, with rounded apical margin, almost as long as first, second and third antennulary segments combined, with one subdistal sensilla on each side at third quarter of its length. Pro- and urosomites without extensions; with a flexible unsclerotized cuticle between prosome and urosome. First urosomite (P5-bearing somite) narrower than preceding somites in dorsal view. Female genital double-somite (genital – second urosomite – and third urosomites fused) completely fused ventrally, with a dorsolateral cuticular rib marking former division between somites. Anal somite trapezoidal, without anal operculum. Caudal rami 1.6 times as wide as long in dorsal view, with seven setae. Female antennule eight-segmented, with aesthetasc and seta fused basally on fourth segment and with apical acrothek on last segment. Male antennule haplocer, 10-segmented, with aesthetasc and seta fused basally on fifth segment, and with apical acrothek on last segment.Antennulary setae typically smooth. Antenna with allobasis and abexopodal seta; exopod threesegmented, armature formula 1-1-1,3,0. Mandibular palp biramous; endopod one-segmented, exopod two-segmented. Maxillule biramous; rami one-segmented. Maxilla with three endites, proximal and middle endites with two, distal endite with three elements; ENP one-segmented. Maxilliped subchelate; (syn)coxa with four, basis with two setae, ENP one-segmented with claw and three accompanying setae. P1–P4 with three-segmented rami. Male P1 basis sexually dimorphic, with inner unipinnate spine and inner modified accessory spine. P1 EXP shorter than ENP, reaching tip of ENP2; EXP2 with inner seta; ENP1 with inner seta; ENP3 longer than the ENP2, with one inner seta, a distal long and geniculate seta, and an outer spine. P2–P4 EXP and ENP of approximately the same length; P2–P4 EXP1 with inner seta; inner distal seta of EXP3 visibly shorter than other elements of same segment; P2 ENP2 with two setae, proximal shorter. Male P2 ENP sexually dimorphic, two-segmented; first segment with one inner seta; second segment with two inner setae, one inner subdistal sigmoid element, one subdistal and one distal seta arising from cylindrical extension fused basally to segment, and one strong distal outer element strongly tapering distally. P5 EXP with six setae in female and male; one or two medial outer elements transformed into short spines. P5 endopodal lobe with five setae in female, with two setae in male; armature of male P5 endopodal lobe strongly bipinnate.

Armature formula of P1–P5 as follows:

Sexual dimorphism expressed in male antennule, P2 ENP, P5, P6, and in genital and third urosomites being separated.

Apomorphies for Bulbamphiascus

We did not detect any apomorphy for Bulbamphiascus . However, Bulbamphiascus is part of a larger monophyletic group composed of Spinodiosaccus gen. nov., Spinopedia gen. nov. and Pallarica gen. nov. ( Fig. 19 ). The subdistal outer element of the male P2 ENP2 with almost parallel margins, viz slightly tapering distally, is considered here as part of the ground pattern of this monophyletic group and is regarded as a potential synapomorphy for this clade. The modification of this spine into a strong tapering element is regarded here as secondary and is a synapomorphy for Bulbamphiascus and Spinodiosaccus gen. nov. The combination of an outer subdistal tapering spine and a sigmoid inner subdistal element on the male P2 ENP2 is unique to Bulbamphiascus (the outer subdistal spine on the male P2 ENP2 of Spinodiosaccus gen. nov. also tapers distally, but the inner subdistal element on the same segment of this species is rather straight).

Bulbamphiascus chappuisi is here relegated to incertae sedis due to the shape of the rostrum and furca, and to the morphology of the male P2 ENP, the illustrations of which (see Rouch 1962: 247, figs 29–33) are too schematic, preventing any further comparison.

Figures

Fig. 19. Strict consensus cladogram of the generic relationships within the Diosaccinae.

Armature formula of P1–P5 as follows: