Neoparmulella, Farias & Neves & Johnsson, 2021

Farias, Amilcar, Neves, Elizabeth Gerardo & Johnsson, Rodrigo, 2021, A new genus and species of Entomolepididae Brady, 1899 (Copepoda, Siphonostomatoida) associated with the endemic octocoral Phyllogorgia dilatata (Esper, 1806) (Cnidaria, Octocorallia) from Northeastern Brazil, Journal of Natural History 54 (35 - 36), pp. 2367-2379 : 2369-2371

Neoparmulella gen. nov.

Diagnosis Body shield showing wide cephalosome in dorsal view, narrow and free second pedigerous somite, followed by plate comprising third and fourth pedigerous somites fused. Urosome mostly not covered by body shield that reaches leg 5 somite. Genital double-somite wider than long and two and three postgenital somites in females and males respectively. All four pairs of legs 3-segmented, third endopodal segment of leg 4 with reduced setation in comparison with other legs. Free segment of leg 5 flattened and leaf-shaped in both sexes.

Remarks Neoparmulella gen. nov. belongs to the family Entomolepididae since it shows a body shield with cephalothorax incorporating first pedigerous somite with posterior plate concealing part of the urosome; posterior plate derived from the fusion of third and fourth pedigerous somites; urosome composed of four somites; caudal rami with 6 setae. Rostrum absent; antennule 17-segmented, therefore within the range of 13 to 18- segmented; antenna with 2-segmented endopod and long, unsegmented exopod; oral cone extremely long, with true siphon. Mandible with slender stylet and 2-segmented palp bearing 2 setae; maxillule bilobed.

The biramous fourth leg with 3-segmented rami and the leaf-like free segment of leg 5, both observed in both sexes of Neoparmulella gen. nov. are unique characteristics, differentiating the new genus from the other Parmulodinae . Parmulella shows a monomerous rudiment in males and a knob in females ( Stock 1992). In Parmulodes Wilson (1944) described the legs of the genus and stated that ‘The first four pairs of legs are biramous and the rami are 3-segmented’ (p. 546), however he did not illustrate them (only legs 1 and 3 – plate 30). Posteriorly Eiselt (1959) redescribed a species also identified as Parmulodes verrucosus , the type described by Wilson (1944), and from a close location. Eiselt (1959) described leg 4 as missing entirely (‘Habitus, das 4. Paar fehlt ganz’) while the legs 1 to 3 were as Wilson stated. Posteriorly Stock (1992) collected specimens from Puerto Rico and CuraÇao and mentioned that Eiselt (1959) redescribed quite satisfactorily the species but mentioned in his descriptive notes that in his specimen ‘The fourth leg is present as a small unsegmented bud bearing a minute distal seta’ and provided an illustration ( Figure 2a in Eiselt, 1959). Based on the need of elucidating the true characteristic of leg 4, Canário et al. (2019) made a loan to study it and a revision was published. According to this study ‘Leg 4 (Figure 6(d)) reduced to a bud bearing a seta’ therefore agreeing with the statement made by Stock (1992), providing a reasonable explanation for the statement of missing entirely from Eiselt (1959) and indicating a possible mistaken interpretation in Wilson´s original description.

In Paralepeopsyllus the fourth and fifth legs were described as completely absent as well as the endopod of leg 3 ( Ummerkutty 1960; Lee and Kim 2017).

Neoparmulella gen. nov. shows two and three post-genital somites on female and male respectively; in both sexes the somites are wider than long. In Parmulodes the same number of somites was observed in both sexes but in females, they are longer than wide ( Stock 1992). In Parmulella both sexes show two post-genital somites wider than long ( Stock 1992). The females of Paralepeopsyllus have two post-genital somites, both longer than wide and the males are unknown in all three species ( Ummerkutty 1960; Lee and Kim 2017).

Parmulodes and Paralepeopsyllus have the body shield covering almost completely the urosome, with only the tips of the caudal rami exposed ( Wilson 1944; Lee and Kim 2017). In the new genus and in Parmulella , as well, the urosome is mostly uncovered, with the body shield reaching partially the genital double-somite ( Stock 1992) or just reaching the somite of leg 5 as in Neoparmulella gen. nov.

Neoparmulella gen. nov. has the free segment of leg 5 flattened and leaf-like in both sexes. In Parmulodes there is no sexual dimorphism as well, but the free segment is very elongated ( Stock 1992; Canário et al. 2019). Parmulella , in contrast to other mentioned entomolepidid genera shows sexual dimorphism with the female leg 5 leaf-like and the male with the free segment clavate. In Paralepeopsyllus the free segment of leg 5 is totally absent.

Etymology Neoparmulella is a combination of ‘neo’, new in Greek, and Parmulella , referring to the genus Parmulella , alluding the similarities between both genera. Parmulella is a diminutive of ‘ parmulla’ meaning small shield.

Figures

Figure 2. Neoparmulella periperiensis sp. nov. female (holotype: UFBA 3302). (a), body, dorsal view; (b), urosome; (c), antennule; (d), antenna. Scale bars: A = 250 µm; B–D = 50 µm.