Taxonomic applications of the esophageal flapper valve in Bairdoppilata and Glyptobairdia (Bairdiidae, Ostracoda), with comments on anatomy, ontogeny, and geography Author Maddocks, Rosalie F. text Zootaxa 2022 2022-08-17 5175 3 301 342 journal article 124035 10.11646/zootaxa.5175.3.1 509d2bb8-bdff-4757-b45a-5d0cbccc31b4 1175-5326 7003585 44FB9C3D-3188-4BFB-BDB8-C1324729A396 Bairdoppilata scaura Maddocks, 2015 ( Figure 16A–B ) 2015 Bairdoppilata scaura Maddocks , n. sp. : p. 298, figs. 6–11. 2018 Bairdoppilata scaura Maddocks. —Maddocks: p. 6, figs. 3B,E,G; 5H, 8P–Q, 10D. Material Examined: Two males and one juvenile from French Frigate Shoals and Kanéohe Bay , the Hawaiian Islands . Dimensions: Holotype male specimen 3360M, LVL 0.830 mm , LVH 0.480 mm , RVL 0.810 mm , RVH 0.430 mm . Paratype male specimen 3864M, LVL 0.810, LVH 0.490 . Paratype juvenile specimen 3359J, LVL 0.748 mm , LVH 0.420 mm . Esophageal Valve: The plate of the holotype ( Fig. 16A ) is relatively broad with slightly curved lateral edges. The posterior perimeter bears about 10 low teeth, mounded to subconical in shape, which are largest near the midline and decrease in size toward the corners. The corner teeth are broader and multilobate. The anterolateral scroll has a hemicircular indentation and curved spine. Another male specimen (3864M) has a plate with about 10 smaller, subconical teeth, which are all about the same size ( Maddocks, 2015 , Fig. 11I ; Maddocks 2018 , Figs. 8Q , 10D ). A second, inner row of approximately 10 slightly smaller teeth seems to be visible through the gaps, or these may be steps at the base of the main teeth rather than separate teeth. The corner teeth are not enlarged, and no multiple cusps can be seen through the setules of the ventral brush. The anterolateral scroll is asymmetrical on the two sides, with poorly developed indentation and broad-based spine. A juvenile specimen (3959J) has a plate with about 12 teeth, with asymmetrically conical outlines, which increase slightly in size away from the midline ( Maddocks 2018 , Fig. 5H ). Indistinct corner teeth are set apart by a gap. The anterolateral scroll has a shallow, curved indentation and broad-based spine. The observed differences between these specimens are mentioned to show the effect of viewing perspective. The plate is naturally curled rather than flat, unless it is compressed in a dissection slide. The teeth project upward (dorsally) as well as outward (posteriorly), so that the apparent shapes of the teeth depend on the angle at which the plate is tilted. In a dissection slide that provides a dorsal view, the plate rests on the ventral bracket, and the angle of tilt depends on the amount of deformation of the bracket walls.