Dinetia, Gómez & Corgosinho & Rivera-Sánchez, 2021

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 : 43-45

Dinetia gen. nov.

urn:lsid:zoobank.org:act:570211A6-5E4D-42CA-A26D-61E2F0E6BC6A

Syn. Bulbamphiascus Lang, 1944: 19 , pro parte.

Type and only species

Bulbamphiascus minutus Dinet, 1971 (= Dinetia minuta ( Dinet, 1971) comb. nov), by monotypy.

Diagnosis

Miraciidae : Diosaccinae . Body fusiform. Width: length ratio of caudal rami 0.8–1.2. Rostrum not fused to cephalothorax, elongate, with rounded tip. Female antennule eight-segmented, with aesthetasc and seta fused basally on fourth segment. Antennulary setae typically smooth. Antenna with allobasis and abexopodal seta; EXP three-segmented, armature formula 1-1-1,3,0. Mandibular palp extremely reduced. Maxillule biramous; rami one-segmented. Maxilla with three endites. Maxilliped subchelate; (syn)coxa with two, basis with two setae; ENP one-segmented, with claw and two accompanying setae. P1–P4 with three-segmented rami. P1 EXP shorter than ENP1, reaching its distal third; P1 ENP1 with strong bipinnate inner seta; ENP3 about twice as long as ENP2, with one small inner seta, a long distal geniculate seta and an outer spine; P1 EXP2 with inner seta, EXP3 with three outer spines, proximal one shortest, and two geniculate distal setae. P2–P4 EXP1 with inner seta; P2–P4 EXP3 with reduced inner armature. P2 ENP1 with inner setae; ENP2 with two setae of approximately same length. Female P5 EXP longer than wide, with six setae – three outer, two distal and one inner element. P5 endopodal lobe with five setae.

Armature formula of P1–P5 as follows:

Male unknown.

Etymology

This genus is dedicated to Alain Dinet for his contribution to the taxonomy of harpacticoid copepods from France. Gender feminine.

Apomorphies for Dinetia gen. nov.

The exclusion of Bulbamphiascus minutus from that genus and from any other genus presented here, and its reallocation into Dinetia gen. nov., is supported by, for example, the lack of the short inner distal seta on P2–P4 EXP3. Bulbamphiascus minutus probably bears a sister-group relationship with Pseudamphiascopsis Lang, 1944 and Rhyncholagena Lang, 1944 , with which it forms a monophyletic group (see Fig. 19 ). These three genera share the longer P1 ENP1 relative to the P1 EXP. Given that B. minutus could not be included in Bulbamphiascus or into any other diosaccin genus, and pending the discovery of the male of this species, we propose a new genus, Dinetia gen. nov., for B. minutus . The assessment and significance of character 43 for D. minuta comb. nov. (see Table 3 ) is still pending until the male is described.

Phylogenetic statistics and resolution

Our partial phylogenetic analysis resulted in 12 most parsimonious topologies with 126 steps, CI of 42, and RI of 77 (see Supplementary File 1). The strict consensus topology (nine branches collapsed) returned the following clades of unclear phylogenetic affinities between each other: a) a small clade composed by Dinetia gen. nov., Pseudamphiascopsis and Ryncholagena; b) a clade formed by Antiboreodiosaccus Lang, 1944 , Diosaccopsis Brian, 1925 , Goffinella Wilson, 1932 , Ialysus Brian, 1927 , Pseudodiosaccopsis Lang, 1944 and Pseudodiosaccus T. Scott, 1906 ; c) a clade formed by Typhlamphiascus Lang, 1944 , Monardius Huys, 2009 , Tydemanella A. Scott, 1909 , Robertsonia Brady, 1880 , Amphiascus Sars, 1905 , Pararobertsonia Lang, 1944 , Sinamphiascus Mu & Gee, 2000 , Pallarica gen. nov., Spinopedia gen. nov., Bulbamphiascus and Spinodiosaccus gen. nov.; d) a clade composed of Amonardia Lang, 1944 , Diosaccus Boeck, 1872 , Pholenota Vervoort, 1964 , Parialysus Nicholls, 1941 , Amphiascoides Nicholls, 1941b , Paramphiascella Lang, 1944 , Robertgurneya Apostolov & Marinov, 1988 , Miscegenus Wells, Hicks & Coull, 1982 , Neomiscegenus Karanovic & Ranga Reddy, 2004 , Paramphiascoides Wells, 1967 , Schizopera Sars, 1905 , Actopsyllus Wells, 1967 , Balucopsylla Rao, 1972 , Eoschizopera Wells & Rao, 1976 , Haloschizopera Lang, 1944 , Helmutkunzia Wells & Rao, 1976 , Schizoperoides Por, 1968 , Protopsammotopa Geddes, 1968 and Psammotopa Pennak, 1942 . The phylogenetic position of the genera Dactylopodamphiascopsis Lang, 1944 , Metamphiascopsis Lang, 1944 and Sarsamphiascus Huys, 2009 remains uncertain. It is important to highlight the high level of character convergence within the Diosaccinae .

Clades a–d above are present in the 12 most parsimonious topologies (see Supplementary File 1), but their relationships are not consistent. The positions of the clade Dinetia gen. nov. – Rhyncholagena and the genera Sarsamphiascus , Metamphiascopsis and Dactylopodamphiscopsis are unclear, sometimes forming a clade with Typhlamphiascus – Spinodiosaccus gen. nov. (6 times), sometimes forming a clade with Amonardia – Psammotopa (6 times). The same happens to the clade Antiboreodiosaccus – Pseudodiosaccus which appears either as the sister group of the remaining Diosaccinae or as the sister group of a clade including Dinetia gen. nov. – Rhyncholagena , Sarsamphiascus , Metamphiascopsis, Dactylopodamphiscopsis and Typhlamphiascus – Spinodiosaccus gen. nov.

Figures

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

Armature formula of P1–P5 as follows: