Bairdoppilata diatreta Maddocks, 2025, sp. nov.

Bairdoppilata diatreta sp. nov. (Graphs 1, 6; Figures 2C–D; 3A–D; 4C–F, I–J, L; 5A–D, L–M; 6A–J; 21O–Q; 32Y–Z; 33 AA–BB) 1974 Bairdoppilata sp. —Maddocks, p. 209 (part; not Pl. 2, figs. 4–7, 18 = Ba. floreana). Derivation of Name: from the Latin adjective diatretus, -a, -um; pierced with holes, filigreed, carved, embossed; to describe the patch pattern. Material Examined: 20 specimens. Types: Holotype specimen 4158 LV, USNM 1751246; Paratype specimen 4157 RV, USNM 1751248; illustrated specimens USNM 1751248–1751253. Type Locality: Florida, UH 1294, Biscayne Bay, off Virginia Key, opposite marine station, water depth 1 m, January 1958. 25 o 44’N, 80 o 09’W. Occurrence: Florida (Biscayne Bay only), East and West Flower Gardens, and Gyre station 7. Dimensions: Holotype specimen 4163 LV, L 0.881 mm, H 0.546 mm. Paratype specimen 4162 RV, L 0.871 mm, H 0.484 mm. Paratype specimen 4156Car, L 0.914 mm, W 0.425 mm. See also Graph 1. Diagnosis: Carapace of moderate length, relatively high, diamond-shaped in dorsal outline; surface densely punctate; opaque patch pattern filigreed with narrow streaks. Description: Carapace narrowly domed, nearly symmetrical; greatest height near mid-length, moderate dorsal overreach, nearly straight anterodorsal and posterodorsal slopes, level ventral margin; blunt caudal process, slightly swollen but not ridged; no swelling at anterior angle (Figures 3B–D; 5A). Dorsal outline only slightly inflated, diamond-shaped, thickest just anterior to mid-length, with straight anterolateral and posterolateral margins tapering symmetrically to narrow ends (Figure 5L–M). Surface densely punctate. Opaque patch pattern filigreed, consisting of swirls and lobes surrounding circular transparent fields, approximately symmetrical in LV and RV (Figures 2C–D; 3A–D). Central opaque patch inverted triangular with rounded edges, with lobate anterodorsal and higher posterodorsal extensions. Irregular, sigmoid stripe connects central spot to dark dorsal surface. Anterior and posterior opaque spots circular, not ventrally extended. Separate marginal opaque spots at mid-anteroventral, mid-ventral, and mid-posteroventral locations. Smaller, lobate spots and curved streaks occupy anterolateral and posterolateral fields, variable in shape but sharply contrasting with transparent regions; in effect, as if large transparent circles had been cut out of formerly continuous opaque regions. Hinge with well-developed ligamental striation; supplemental dentition sharply executed (Figure 6E–J). ZC broad, vestibules very narrow; selvages straight to weakly curved, nodular zones of flange narrow to moderately wide (Figures 3D; 6A–B). Aligned pores of RPC visible within gape in ventral view (Figure 5M). LV and RV anteroventral and posteroventral margins smooth or with remnants of frill; (Figures 3C–D; 6C). Juvenile A–1 RV anteroventral margin smooth, posteroventral margin with uneven frill; with dense punctation and opaque patch pattern similar to adult (Figure 4C–F). Remarks: Ba. diatreta is similar to Ba. collaevata, but smaller, with more conspicuous punctation, and the opaque patch pattern is more delicate. In Graph 1, the LV cluster is offset (up and to the right) relative to the RV cluster (down and to the left), by the usual magnitude for bairdiids. The RV cluster overlaps with the RV cluster for Ba. collaevata, but there is no overlap of the LV clusters. LV from the Flower Gardens and the Gyre station are distinctly higher, relative to length, than those from Florida. At any one locality, it is likely that the larger individuals are females, but it is difficult to assess sexual dimorphism because of the small number of specimens (Table 1). Maddocks (1974) reported Bairdoppilata sp. from the Flower Gardens, but four species were included in the material: Ba. collaevata, Ba. diatreta, Ba, fithianae, and Ba. floreana. The illustrations are of Ba. floreana. The statement that the species is living in Bermuda applies only to Ba. fithianae.