Neonesidea florea, Maddocks, 2021

Maddocks, Rosalie F., 2021, Taxonomic applications of the esophageal flapper valve in the Genus Neonesidea (Bairdioidea, Podocopida, Ostracoda), including descriptions of new and poorly known species from the Caribbean and Gulf of Mexico, Zootaxa 4903 (4), pp. 451-492 : 465-470

Neonesidea florea n. sp.

( Figures 6 A–R, 7A–V, 8A–L; Graphs 1, 3)

1974 Neonesidea dinochelata Kornicker [sic].—Maddocks, p. 208, Pl. 2, figs. 1–3.

Material: Three adult males, more than 40 adult and juvenile subfossil specimens.

Holotype: Male specimen 975M from UH 1494, West Flower Garden.

Etymology: Latin floreus, -a, -um; rich in flowers, flowery.

Dimensions. Male specimen 974M from UH1494, West Flower Garden: LVL 0.711 mm, LVH 0.346 mm, RVL 0.701 mm, RVH 0.338 mm. Holotype male specimen 975M from UH 1494, West Flower Garden : LVL 0.710 mm, LVH 0.353, RVL 0.689 mm, RVH 0.335 mm. See also Graphs 1, 3.

Description. The male carapace is smooth, boxy to lozenge-shaped, thickest at mid-length and below midheight, with an obliquely bent ventral surface. In lateral outline it is oblong to subrhomboidal, with broadly curved dorsal margin, steeply sloping posterodorsal margin, obliquely curved anteroventral margin, and level ventral margin with slightly upturned posterior angle. In dorsal outline it is elliptical, only moderately inflated, with gently curving sides and nearly symmetrically rounded anterior and posterior ends. The female carapace is a little longer than that of the male and higher in proportion to length. Well-conserved specimens have dark yellow to brown endocuticle lining the valve interior. There is an irregular transparent region above the eye in each valve, but otherwise only the marginal zones (duplicatures) are clear. There is no patch pattern. The AMS consists of four elongate, wedge-shaped to cuneiform scars in zigzag arrangement. The free margins are edged, as usual, with a narrow flange of uncalcified cuticle, which is especially noticeable at the anteroventral angle (mouth region), but marginal denticles and frills are absent or indistinct. Numerous NPC with narrow walls are densely arrayed over the valve surface. The carapace sensilla are short, thick, sharply tapered, and may be barbed or thorny near their bases. There are no plumose setae above the anteroventral angle.

The male antenna has a short, curved terminal claw ending in a bifid hook, which is a diagnostic trait for the Genus Neonesidea .

The zygum (medial supporting structure for the paired hemipenes) begins with a U-shaped frame of heavy struts, from which elegantly bowed lamellar pieces project laterally. The stout basal segment of the hemipenis articulates with the anterior ends of the U-strut and the lamellar wing. The median segment is half-ovate and narrow outside (dorsally), expanding distally and inside to contain and support the copulatory tube and the terminal segment. The short, diagonally-articulated terminal segment carries two appendages. The upper appendage is thumblike, thick-walled, and projects more or less dorsally. The end of this thumb carries an arched, finger-like extension and a forked aesthetasc. The other conspicuous appendage is a broad anterodistal lamella, which is flexed in halfcylindrical form, sharp-edged, and asymmetrical, terminating distally in one sharply pointed and one broadly lobate corner. A short, arched copulatory tube arises at about midlength on the median segment and is tethered distally to the end of the thumb-like process of the terminal segment.

The ring and plate of the esophageal chewing structure are dark brown. The plate is wedge-shaped with straight, converging sides. It is apparently flat and transparent enough that the ventral setules show through as a striate texture in dorsal view. The posterior margin is smooth-edged and broadly scalloped, with wide, low, undulating ledges. The corners are bluntly curved lobes. There are no medial or corner teeth. The bracket is a fused, subpyramidal structure with short posterior horns and anterior tubercles.

GRAPH 3. H/L scatter plot for adult and juvenile LV and RV of N. florea , n. sp. from the West Flower Garden and Belize. LV and RV have very nearly the same proportions. The cluster of adults is elongate, displaying sexual dimorphism of size but not shape. Known females plot in the upper right of the adult cluster, while known males plot in the lower left.

GRAPH 4. H/L scatter plot for LV (only) of N. caraionae n. sp., N. gerda , N. longisetosa , and N. omnivaga . The adults of each species occupy a separate area, adjacent to but not overlapping the other species, while juveniles of each species tend to plot between the instar-clusters of other species. The two male specimens of N. caraionae (open circles) are slightly longer than females of N. longisetosa , although about the same height, and they are much larger than males of N. longisetosa .

Remarks: N. florea is much smaller than N. dinochelata , and less inflated dorsally and medially. In carapace proportions, N. florea is smaller, more elongate, less inflated dorsally, and lacks the terminal spine of N. equatorialis Coimbra & Carreno (2002 , p. 194, Pl. 2, figs. 23–26) on the Brazilian equatorial shelf.

A similar hemipenis was illustrated for a male specimen of N. dinochelata from Bimini by Maddocks (1969, Fig. 12F ), but that drawing shows less sharply pointed distal corners on the anterodistal lamella, and the aesthetasc is missing or indistinct. Additional anatomical investigation is needed to verify the diagnostic attributes of these two species.

The plate is very similar to those of N. baccata and N. edentulata , but those Hawaiian species are readily distinguished by details of the carapace and hemipenis.

Distribution: N. florea is common on the Flower Gardens Banks of Texas. It has also been seen in a sample from the Belize platform.

Figures

FIGURE 6. Neonesidea florea n. sp. A–H, specimen 974M; I–R, specimen 977M; both from West Flower Garden. A, A2 claw; B, DV of plate edge; C, DV of EV with ring, plate, bracket and braces; D–E, right and left hemipenis and furca; F, distal end of hemipenis, with tip of copulatory tube and forked aesthetasc; I, DV of EV with ring, plate, bracket and braces; J, DV of compressed head capsule, including EV with ring, plate, bracket, and braces, as well as mouth region (lower left) and basal podomeres of A2 (lower right); K, hemipenis with zygum; L, hemipenis; M–N, RV and LV exteriors in TL; O–P, RV and LV exteriors in RL; Q–R, AMS and NPC of RV and LV. Scale bar = 50 µm.

FIGURE 12. Neonesidea longisetosa (Brady). A–O, subfossil specimen 4045M from Belize; P–Q, specimen 1652M from the Bahamas; S, subfossil specimen 4053W from Jamaica. A. A–D, hemipenis, with distal details; E, corner tooth of plate; F–G, VV of plate at high and low focus; H, interior of posteroventral region of RV, showing dry fragments of plate and ring; I–L, diagonal view of plate standing upright within RV interior, from high focus to low focus; M–N, edge view of posterior margin of same plate after removal from valve, showing pyramidal teeth and row of ventral setules, the dorsal surface is up (concave); P–R, hemipenis, with distal details; S, VV of EV with ring and plate. Scale bar = 50 µm.