“ What’s in a name? ” Bairdia fasciata Brady, 1870, and two new Caribbean species of Bairdoppilata (Bairdiidae, Podocopida, Ostracoda) Author Maddocks, Rosalie F. 0000-0002-5486-5072 Department of Earth and Atmospheric Sciences, Room 312 Science & Research Building 1, University of Houston, Houston, TX 77204 - 5007, USA. RMaddocks@uh.edu Author Horne, David J. 0000-0002-2148-437X School of Geography, Queen Mary University of London, Mile End Road, London E 1 4 NS, UK. & Earth Sciences Department, The Natural History Museum, Cromwell Road, London, SW 7 5 BD, UK. d.j.horne@qmul.ac.uk text Zootaxa 2024 2024-05-13 5448 3 371 400 http://dx.doi.org/10.11646/zootaxa.5448.3.3 journal article 296639 10.11646/zootaxa.5448.3.3 95539a45-2179-477b-875f-3cab2ff0594d 1175-5326 11231896 6907E847-FE33-47AD-9F0A-B8AF763515A8 Bairdoppilata parvafasciata , n. sp. ( Figs 8 , 9A–S , 10A–V ; Tables 1 , 3 ) Not 1870 Bairdia fasciata n. sp. —Brady, 193, pl. 19, figs. 20, 21. Not 1975 Bairdoppilata (Bairdoppilata) fasciata (Brady) —Teeter, p. 420, figs. 3g , 4e [= Ba. magnafasciata n. sp. ] ? 1982 Bairdia gerda Benson and Coleman —Llano, p. 77, Pl. 1, fig. C 1 . ? 2021 Bairdoppilata sp. 1 —Bernal, p. 57, Pl. 7, figs. 23–26. Material Examined: 254 subfossil valves and carapaces. Types: Holotype specimen 4084LV, USNM 1607074 , a dry LV, presumed female, from Belize , sample 2742 . Paratype specimen 4085 RV , USNM 1607075 , a dry RV , sex indeterminate, from the same sample, Belize . Type locality: Belize carbonate shelf, near Caye Chappel , western Caribbean Sea.Approximate Lat. 17 o 41’44”N , Long. 88 o 02’19”W . 300–400 feet (91–122 meters) from shore, windward side of island, inside of barrier reef. Water depth 20–25 feet (6–8 meters) . Derivation of Name: Latin, parvus , small; plus fasciatus , banded, striped, bundled. Dimensions: Holotype specimen 4084LV, USNM 1607074 : L 0.897 mm , H 0.535 mm . This specimen plots within the upper part of the adult LV cluster ( Fig. 8 ) and is likely to be a female. Paratype specimen 4085 RV , USNM 1607075 : RV L 0.907 mm , H 0.498 mm . This specimen plots near the middle of the adult RV cluster ( Fig. 8 ) and could be either sex. The dimensions for all illustrated specimens are given in Table 3 . The H:L scatter plot ( Fig. 8 ) shows evident size dimorphism, with presumed females being both longer and higher than males but similar in shape. This is a common pattern in bairdiids. Occurrence: Belize , Cozumel, Cuba , Grand Cayman, and Roatan ( Table 1 ). The species has been sought but not seen in assemblages from the Bahamas , Bermuda , Jamaica , the Florida Keys, and the Flower Gardens in the Gulf of Mexico. Apparently, the species was not recognized by Teeter (1975) in his Belize assemblages. A LV of this species may have been illustrated from the Bay of Cartagena, Columbia, by Llano (1982, Pl. 1, fig. C 1 misidentified as Neonesidea gerda ). Bernal (2021 , p. 57, Pl. 7, figs. 23-26) may have reported this species as “ Bairdoppilata sp. 1 ” from the lagoon of Serrana Atoll ( 78 specimens in 21 samples from an 80-cm sediment core). The dimensions provided (LV L 0.85 mm , H 0.51 mm ; RV L 0.85-0.88 mm , H 0.47-0.49 mm ) plot within the lower end of the respective clusters for P. parvafasciata ( Fig. 3 ). Serrana Bank is an underwater atoll and coral reef, located on the continental slope of Nicaragua but administered by Columbia , at 14 o 20’N , 80 o 20’W . It is included within the UNESCO Seaflower Biosphere Reserve (https://en.unesco.org/biosphere/lac/seaflower). FIGURE 8 . Bairdoppilata parvafasciata , n. sp. H:L scatter plot for 226 specimens, by collecting locality. Dimensions for intact carapaces are included with LVs. Presumed females plot toward the upper right of the adult cluster, and presumed males plot toward the lower left. Adult and three juvenile instars are represented in these assemblages. The dimensions of illustrated specimens are given in Table 3. FIGURE 9 . Bairdoppilata parvafasciata , n. sp. A–G , from Belize; H–K , from Grand Cayman; L–S , from Roatan. A–I, L–S , adults; J–K , juvenile instars. A, H, J, RV exterior; B, L, P, right-lateral views of carapace; M, Q , left-lateral views of carapace; C, N, R , dorsal views of carapace, anterior end is up; D, I, K, LV exterior; E , LV interior; F, G , posterior and anterior supplemental dentition, LV interior; O, S , ventral views of carapace, anterior end is up; all in reflected light. A , specimen 4085RV; B–C , specimen 4121Car; D–G , Holotype specimen 4084LV; H , specimen 4087RV; I , specimen 4086LV; J , specimen 4090RVj; K , specimen 4089LVj; L–O , specimen 4109Car; P–S , specimen 4110Car, the hole at the hingeline may be a predation scar. Bar scale = 100 micrometers. FIGURE 10 . Bairdoppilata parvafasciata , n. sp. A–K , from Belize; L–P, from Grand Cayman; Q–R , from Cuba; S–V , from Roatan. A–G, N–V , adults; J–K, juvenile instars. A, C, E, G, J, L, N, S, U , RV exteriors; B, D, F, H, I, K, M, O–R, T, V, LV exteriors; all in transmitted light. A, specimen 4117RV; B , specimen 4120LV; C , specimen 4085RV; D , Holotype specimen 4084LV, with small predation scar on posterolateral flank; E , specimen 4118RV; F , specimen 4119LV; G , specimen 4115LVj; H , specimen 4116LVj; I , specimen 4122LVj; J , specimen 4123RVj; K , specimen 4124LVj; L , specimen 4090RVj; M , specimen 4089LVj; N , specimen 4087RV; O , specimen 4086LV; P , specimen 4088LV; Q , specimen 4130LV; R , specimen 4131LVj; S , specimen 4114RV; T , specimen 4112LV; U , specimen 4113RV; V , specimen 4111LV. A, F, I, N, post-mortem fungal or microbial boreholes are evident. Bar scale = 100 micrometers. TABLE 3. Bairdoppilata parvafasciata , n. sp. List of illustrated specimens, with dimensions (in micrometers) and provenance. H = Holotype, P = Paratype. Description: Carapace smooth, oblong to loaf-shaped in lateral outline ( Figs 9B, L, P ), highest slightly anterior to mid-length in lateral view at smoothly curving anterodorsal angle; mid-dorsal margin short; posterodorsal angle broadly rounded but definitely indicated; posteroventral margin sloping steeply; ventral margin nearly level, with broad but very shallow ventral indentation.There is substantial overreach of LV over RV along dorsal and posterodorsal margins, less along anterodorsal and midventral margins, and none along anteroventral and posteroventral margins. In dorsal view the carapace is inflated medially, thickest at mid-length, with moderately rounded anterior end and gently curved sides; posterior to this central swelling, both valves are constricted, but the RV is more so, just in front of the narrowly rounded posterior end ( Figs 9C, N, R ). Lateral outline of LV high-arched, upright, asymmetrical, with broadly but obliquely rounded anteroventral margin, long and weakly curved anterodorsal margin, short and sloping mid-dorsal margin, steeply sloping posterodorsal margin, obliquely up-curving posteroventral margin, and gently indented ventral margin ( Figs 9D, I ; 10B, D, F, O–P, T, V ). Anterodorsal and posterodorsal angles obtuse, broadly rounded but distinct; posterior angle obtuse but well defined, slightly caudate, emphasized by slight sinuosity of dorsal margin just above posterior angle. Lateral outline of smaller RV necessarily more angulate, with more clearly indicated anterodorsal, posterodorsal, and posterior angles, well-marked anteroventral angle, and shallow but consistent ventral indentation ( Figs 9A, H ; 10A, C, E, N, S, U ). Hinge bairdiid, with no special features, all elements narrow because of the thin carapace wall ( Fig. 9E ). Supplemental bairdoppilatan dentition consists of about 6 small denticles on anterodorsal and posterodorsal edge of the RV; the LV has about 6 small locules on infold beneath anterodorsal and posterodorsal overhangs ( Figs 9F, G ). The supplemental denticles are hard to see, because the valve edge is thin, hardly widened in this region, and the denticles are not much larger than the striated texture of the valve wall. In the LV, the row of locules is located in the crease right under the overhang, only visible if the valve is tilted, and the usual swelling of the infold ventral to the locules is poorly developed. Valve margins smooth, without marginal spines. Marginal infold of moderate breadth with anterior and posteroventral vestibules. NPC and false RPC numerous, radiating laterally outward and superposed near margins. Adductor muscle scar pattern bairdiid, with about 9 scars arranged in 3 rows in a loose rosette. Each valve has a distinctive patch pattern of clear and opaque regions. In the LV the central opaque spot (1) is large and shield-shaped, with a nearly flat top; an irregular posterodorsal extension connects with the mid-dorsal spots ( Figs 9D, I ; 10B, D, F, O–P, T, V ). Within the anterodorsal part of the central opaque spot a tiny transparent oval is consistently present, and the region over the muscle scars may be somewhat more transparent. The lower tip of the central spot may extend almost to the ventral indentation, or that ventral region may be clear. Other opaque spots in the LV include (2) a large, triangular posterodorsal spot, which extends to the posterodorsal margin; (3) smaller circular or irregular spots at the anterior and posterior angles; and (4) two small mid-dorsal spots, which may connect to the posterodorsal extension of the central spot by peninsulas or islands. In the RV the pattern of spots is similar, nearly symmetrical ( Figs 9A, H ; 10A, C, E, N, S, U ). In less well conserved specimens the pattern is more difficult to discern, because of post-mortem cloudiness, abrasion and corrosion. The patch pattern is easily recognizable in late juvenile instars, which have smaller but more sharply defined spots and more transparent surrounding fields Figs 9J–K ; 10G–M ). The soft parts are unknown. Comparisons: Bairdoppilata parvafasciata n. sp. is similar to B. magnafasciata , which also occurs in these assemblages ( Table 1 ). It differs by its smaller size, more upright and broad-shouldered lateral outline, more distinct posterodorsal angle, more truncate posterior margin, more caudate shape and lower placement of the posterior angle, and the triangular shape of the large posterodorsal opaque spot. From Ba. cushmani Tressler, 1949 , which has a somewhat similar lateral outline and occurs abundantly throughout the Caribbean ( Maddocks 2022 ), it may be distinguished by its smaller size, less angulate lateral outline, the less exaggerated caudal angle, and the single posterodorsal spot (rather than two spots). Late juvenile instars of these three species can be separated by careful attention to the opaque spots. The differences of shape are less marked in the juveniles. Bairdoppilata parvafasciata resembles Ba. cytheraeformis Hartmann, 1974 , described from the coast of Angola . It is smaller, with less elongate proportions, a less rounded lateral outline, a slightly more convex dorsal margin, and a more distinctly truncate posterior end. Bairdoppilata parvafasciata somewhat resembles Ba. vitoriensis Da Luz & Coimbra, 2023 , described from the coast of Brazil . It is substantially smaller and not as high relative to length. In lateral outline it is less exaggerated, with less elevated dorsal margin and a less abruptly truncated posterior end. Remarks: No geographic trends are evident in size or shape, apart from likely sexual dimorphism ( Fig. 8 ). Bairdoppilata parvafasciata is the smaller of the two Caribbean species,the larger species being Ba.magnafasciata n. sp. (see above). It is represented in 17 of the 29 assemblages studied here, but in less total abundance than Ba. magnafasciata ( Table 1 ). It tends to occur in the coarser sands and coralline rubble near a reef tract, rather than in the shallow-water sands of quieter platform and lagoonal environments.