Neonesidea Maddocks-Danielopol 1969
Creators: name: Maddocks, Rosalie F.
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Ostracoda
Podocopida
Bairdiidae
Neonesidea

description: Genus Neonesidea Maddocks, 1969
1969 Neonesidea Maddocks: 16.
1972 Neonesidea Maddocks—Danielopol, p. 42.
1995 Neonesidea Maddocks—Maddocks, p.199.
2013 Neonesidea Maddocks—Maddocks, p. 466.
Supplemental Description. The carapace (ex., Fig. 11 I–M) is more or less fusiform with smoothly curving lateral and dorsal outlines. The two valves are almost the same size, with only minimal LV overlap. Females are longer than males and may be higher in proportion to length. The LV and RV have nearly equal size and fairly similar outlines. As always in Bairdiidae, the LV has more rounded contours with some dorsal overreach and a nearly level or convex ventral margin, while the inserting RV necessarily has more marked dorsal angles and a more pronounced ventral indentation.
The surface is smooth or undulating, never punctate. The posteroventral angle is subacute and sharply marked. In each valve, the margin just above the posteroventral angle is subtly flared or caudate (ex., Figs. 11 N–P). The posterodorsal caudal gape is protected on each valve by a row of enlarged, fan-shaped, plumose setae (ex., Figs. 16L), which rise from enlarged, slightly elevated pores near (not at) the valve edge. The LV typically has numerous small, tapering, slightly curved posteroventral marginal denticles (ex., Fig. 4I), and the posteroventral angle may be prolonged by a larger spine (ex., Fig. 11 N–P). Anteroventral marginal denticles, if present, are less conspicuous. The RV may have narrow anteroventral and posteroventral marginal frills (ex., Fig. 4J). Simple NPC of many sizes, mostly without walls and furnished with simple sensilla, are numerous (ex., Figs. 13D). The patch pattern always includes a central opaque spot, and smaller, less clearly defined opaque spots may be present at the anterior, anterodorsal, posterodorsal and/or posterior angles (ex., Figs. 11 J–M).
The plate of the esophageal flapper valve is wedge-shaped in dorsal profile with slightly bowed to nearly straight sides. In typical species, the curved posterior margin carries about 6 to 10 low, conical to mound-like teeth, arranged symmetrically on either side of a narrow medial gap. Because these teeth project diagonally upward (dorsally) as well as outward (posteriorly), the zigzag silhouette in photographs varies according to the tilt of the plate and viewing angle (ex., Figs. 12 F–G, I–H, and N–O are all views of the same specimen). Their profiles range from triangular to rounded-conical to low mounds. Usually, the largest teeth are medial, and their size decreases laterally. A lateral gap, containing no teeth or tiny, irregular teeth, separates the posterior teeth from a prominent, compound or multilobate corner tooth. This configuration is typical for species of the N. schulzi and N. tenera species-groups (informal).
A different configuration is seen in species of the N. dinochelata species-group (informal), in which the plate has no teeth at all (ex., Figs. 6B, C, I; 7 L–M, U–V). The posterior perimeter curves smoothly on either side of a narrow medial gap, producing two broad lobes. A variant form has four broad lobes separated by small clefts (ex., Fig. 3C). Rather broad lateral gaps separate the central lobes from asymmetrical, horn-shaped extensions (winglets) at the corners. The posterior margin of the plate may be smooth or edged with very short, discontinuous lamellae, and it may be emphasized by a darker stripe.
Remarks. The key character uniting species into the Genus Neonesidea is the bifid hook of the distal claw of the adult male antenna (ex., Figs. 13A, 16B). Slight variations in the shape of this hook have been noticed, but in the current state of our knowledge they do not contribute reliably to diagnosis of species. Some apparent differences in shape of the hook may result from damage or viewing angle, while others may be related to the overall proportions of the limb. Unfortunately, this hook is thin, not heavily sclerotized, and carried on the flexibly-jointed terminal podomere of the A2. This terminal podomere and claw are nearly always missing from the dry fragments, which are occasionally retained within subfossil carapaces of individuals that were living at the time of collection. Females have a tapered terminal claw without any hook (ex., Fig. 15D), and the dimorphic accessory seta is long (vs. short in males); unfortunately this seta is thin and unlikely to be recognizable in dried specimens.
Maddocks (1995) erroneously described several species of Neonesidea as “punctate.” Puncta are incised circular depressions that do not penetrate the carapace like NPC. Puncta are not present in Neonesidea. The uneven or undulating texture of the valve surface in some Neonesidea is an artifact of the closely spaced NPC (ex., Fig. 8O).
Species-Groups. Maddocks (1969, p. 20) suggested that informal species-groups may be recognized within the genus Neonesidea, three of which were tentatively designated as the N. schulzi, N. tenera and N. dinochelata species-groups. The species of each group share general resemblances in carapace shape, proportions and sensilla. The first two groups have basically the same configuration of the esophageal flapper valve, while the third has a more reduced presentation. Corresponding distinctions in the A2, hemipenes, and other soft parts remain elusive, however. A few other species do not adhere to any of these groups, or, indeed, to each other. At present, it is best to treat these species-groups as informal generalizations rather than taxonomic categories.
The 17 species described below are listed in alphabetical order. They may be assigned tentatively to informal species-groups as follows: To the N. schulzi species-group: N. caraionae n. sp., N. gerda, N. holdeni (?), N. longisetosa, N. omnivaga, N. schulzi. To the N. tenera species-group: N. decipiens, N. manningi, N. mediterranea, N. plumulosa, N. tenera. To the N. dinochelata species-group: N. bacata, N. credibilis n. sp., N. dinochelata, N. sp. aff. N. dinochelata, N. edentulata, N. florea n. sp.
description: Published as part of 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, pp. 451-492 in Zootaxa 4903 (4) on pages 454-455, DOI: 10.11646/zootaxa.4903.4.1, http://zenodo.org/record/4431228