Bairdia fasciata Brady, 1870

Maddocks, Rosalie F. & Horne, David J., 2024, “ What’s in a name? ” Bairdia fasciata Brady, 1870, and two new Caribbean species of Bairdoppilata (Bairdiidae, Podocopida, Ostracoda), Zootaxa 5448 (3), pp. 371-400 : 373-375

Bairdia fasciata Brady, 1870

( Figs 1 , 2 )

1870 Bairdia fasciata Brady n. sp. —193, Pl. 19, figs. 20, 21.

Material Examined: One carapace (the holotype) .

Nomenclatural Remarks: The G.S. Brady Ostracod Collection, formerly in the Hancock Museum in Newcastleupon-Tyne (renamed the Great North Museum: Hancock in 2009), is now kept in the Great North Museum Resource Centre at the Discovery Museum in the same city. Catalogue numbers are prefixed by NEWHM. Two slides are listed for Bairdia fasciata in the online catalog for the G.S. Brady Collection on the website of the Hancock Museum:

http://greatnorthmuseum.org.uk

https://collectionssearchtwmuseums.org.uk/#browse=enarratives.17433

https://collectionssearchtwmuseums.org.uk/view=list&id=c15e&modules=ecatalogue&name= Bairdia %20fasciata &ColObjectStatus=Current

[ NEWHM 1.16.44 : Ostracod, Bairdoppilata fasciata ( Brady, 1870) Teeter, 1975 .] This is a white, one-hole, Curtin paper microslide with a red dot, stated to contain a type specimen, the holotype. It is labeled (in pencil, overwritten in black ink) in Kenneth G. McKenzie’s handwriting: “ Bairdia fasciata Brady, 1869 (Fonds). B97. HOLOTYPE. Loc: St Vincent, Cape de Verde Islands. KGM 1967” (the last only in pencil). The attributions to Bairdoppilata and Teeter, 1975 are additions to the online catalog and do not appear on the slide.

This specimen is eligible to be a holotype, if it was the only specimen formerly contained in the red slide ( NEWHM: 2.05.44, described below), in which case original designation by monotypy would apply. But, if the specimen was selected out of multiple syntypes in the red slide and transferred to the white slide, in preparation for a manuscript that was never published, then its intended status would have been lectotype, not holotype. In either case, a type notation in an unpublished museum catalog has no nomenclatural status and does not constitute fixation of a type ( ICZN 1999, p. 77, Article 72.4.7).

Kenneth G. McKenzie studied many slides from the Brady Collection during the 1970s, but he never published his observations on B. fasciata .

[ NEWHM: 2.05.44 : Bairdoppilata fasciata ( Brady, 1870) Teeter, 1975 .] This is a red paper microslide, stated to contain multiple species. It is labelled in G.S. Brady’s handwriting: “ Bairdia fasciata B., Cythere curvirostrata B., St. Vincent, Cape de Verd.” It is now empty, and the specimen in the white slide may be eligible to be a holotype by monotypy. If the red slide formerly contained multiple syntypes, then selection of a lectotype would be required. In either case, mention as “Type” in a museum catalog and on the slide label does not constitute type designation, because it is unpublished. Again, the attributions to Bairdoppilata and Teeter, 1975 are additions to the online catalog and do not appear on the slide.

These two slides were studied at the Discovery Museum by one of us ( DJH) on 1. September 2022 with the following observations:

The holotype of B. fasciata (1.16.44) is one of the specimens removed from the original Brady slide (2.05.44) by K.G. McKenzie (while based at the Natural History Museum in London ) and retained for further study, and subsequently returned to the Hancock Museum in the early 1980s.Assuming this was the only “ Bairdia ” specimen on the original (red) slide, then McKenzie’s designation as holotype seems correct; there is no evidence that additional specimens were ever on the slide.

Designation of Holotype: It appears that the single carapace (now in the white slide 1.16.44) is the holotype by monotypy, as presumably intended by K.G. McKenzie and G.S. Brady.

Taxonomic Remarks: Bairdia fasciata was described by Brady (1870) from a dredging in the harbor of São Vicente Island (16 o 51’N, 24 o 58’W) in the northern group of the Cape Verde Archipelago in the North Atlantic—not from St. Vincent Island in the Caribbean, as stated erroneously by Teeter (1975, p. 421). The description is in Latin (a loose translation follows):

“ Testa a latere visa subreniformis, altitudine maximâ dimidiam longitudinis vix superante in medio sitâ; extremitate anticâ rotundatà, posticà subrotundatâ, suprà médium valdè declivi, margine superior arcuato in medio penè gibboso, inferiore distincte sinuato; suprà visa ovata, extremitatibus acuminatis, latitudine maximâ altitudine multò minore in medio sita. Testa tenera , pellucida, fasciis transversis albidis, opacis, pilis brevissimis parcè vestita.”

“Shell subreniform in lateral view, with maximum height barely exceeding half of length, located at the middle; rounded in the anterior end, subrounded in the posterior, with the upper margin arched in the middle, almost humped, the lower margin distinctly sinuated; ovate as seen from above, with acuminate extremities, maximum width much less than height, located in middle. Shell delicate, transparent, with transverse white and dark bands, sparsely covered by very short hairs.”

Brady’s description is vague, and many of the traits mentioned are not diagnostic. His drawings give an idea of carapace shape, with perhaps some distortion, but homeomorphy is ubiquitous in smooth Ostracoda. Brady’s pl. 19, fig. 20 (reproduced here as Fig. 1 ) illustrates a LV exterior that is almost twice as long as high, with a H:L ratio of only 0.55. The lateral outline is lozenge-shaped, unusually elongate for a bairdiid, having a sinuous dorsal margin with shallow concavities in front of and behind a mid-dorsal peak, and a deeply indented ventral margin. The patch pattern (?) has a broad, oval central streak, possible smaller anteromedian and posteromedian circular spots, and very large posterodorsal and posteroventral opaque spots, which are almost merged. The marginal zone may be somewhat narrow. The dorsal view (Brady’s pl. 19, fig. 21) shows a rather compressed, smoothly tapering carapace with greatest thickness located medially. The length was specified as 0.9 mm.

The holotype specimen is a dry, closed carapace, which appears to be an adult with a reasonably broad inner lamella ( Fig. 2C , photograph of left side taken by DJH). It is perhaps slightly tilted (dorsal region downward). The central opaque spot is rather large and extends as a thick streak almost to the dorsal margin. Small anterior, posterodorsal, and posterior opaque spots are barely discernable. In lateral outline, the dorsal margin is very broadly and smoothly arched, with no suggestion of the mid-dorsal “hump” emphasized by Brady. The posterior margin is obscurely angled without any sinuation or caudal process. The ventral margin has a broad, shallow indentation. Of the two new species described below from the carbonate platform of Belize, this specimen more closely resembles the larger species ( Ba. magnafasciata n. sp.) in outline and patch pattern, although its proportions are more elongate.

The taxonomic status of B. fasciata remains uncertain. With only a single specimen, variability and sexual dimorphism cannot be evaluated. The presence or absence of supplemental dentition (diagnostic for the Genus Bairdoppilata ) cannot be determined from this closed carapace, and so Teeter’s reclassification of B. fasciata into Genus Bairdoppilata cannot be confirmed. The carapace length given by Brady for B. fasciata would correspond to an adult of the smaller species described below from Belize ( Ba. parvafasciata n. sp.), but an A–1 instar of the larger species ( Ba. magnafasciata n. sp.) ( Fig. 3 ). On the other hand, the lateral outline and carapace proportions more closely resemble the larger species ( Ba. magnafasciata n. sp.), except for the ventral indentation. Until these discrepancies can be resolved by redescription of a larger population at the type locality, it will be difficult to recognize B. fasciata at other localities.

Under this species name, but with reclassification in Bairdoppilata, Teeter (1975) reported a species from the carbonate platform of Belize. Perhaps because he did not realize that he was proposing an amphi-Atlantic distribution, Teeter did not discuss the merits of this species identification. His description mentions a “low dorsal hump,” but no such hump is visible in his illustrations. His fig. 3g shows an intact carapace (right side) with a smooth exterior, an asymmetrical diamond-shaped central opaque spot, perhaps a small posterodorsal spot, and small anterior and posterior spots; the lateral outline is rather ordinary, and the H:L proportions are much less elongate than Brady’s illustration. The slight dorsal overreach of LV over RV, which might be the “hump” Teeter referred to, is minimal for Bairdiidae . An accompanying drawing (Teeter’s fig. 4e) shows the interior of a right valve with an asymmetrical, heart-shaped central spot and small anterior, posterodorsal, and posterior opaque spots. The marginal characters in this drawing are somewhat idealized, showing a short hingeline, minute supplemental denticles along the anterodorsal and posterodorsal edges, a rather broad inner lamella, unusually deep anterior and posterior vestibules, and numerous straight, separate, parallel RPC.

Teeter claimed that the patch pattern of his Belize population resembles that of Brady’s drawing, but he did not describe the details. Although he had only 6 specimens in 3 samples and no soft parts, he stated that the sexual dimorphism is “pronounced.” The two sets of dimensions he provided plot within the female and male clusters for the larger species proposed below from the Belize platform ( Ba. magnafasciata n. sp., Fig. 3 ). The smaller species ( Ba. parvafasciata , n. sp.) apparently was not recognized in Teeter’s assemblages.

Figures

FIGURE 1. Brady’s (1870) drawings of Bairdia fasciata. Plate 19, fig. 20, Left valve, side; fig. 21, above.

FIGURE 2. Bairdia fasciata Brady, the holotype.A. The white slide 1.16.44 is labelled in Kenneth G. McKenzie’s handwriting: “Bairdia fasciata Brady, 1869 (Fonds). B97. HOLOTYPE. Loc: St. Vincent, Cape de Verde Islands. KGM 1967 (in pencil)”. It contains a single carapace, which is illustrated in Fig. C. B. The red slide 2.05.44 is labelled in G. S. Brady’s handwriting: Bairdia fasciata B., Cythere curvirostrata B., St Vincent, Cape de Verd. There are no specimens on this slide. C. Low-resolution snapshot of the carapace in the white slide. “The holotype is cloudy white, but with a little adjustment of lighting it shows a saddle-shaped opaque area. The image is tilted to compensate for the tilt of the mounted specimen, but there may still be a slight distortion of the actual outline (it may look a little more elongate than it actually is)” (observations by DJH 1 September 2022).

FIGURE 3. Bairdoppilata magnafasciata, n. sp. H:L scatter plot for 335 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. The dimensions reported by Teeter (1975) plot within the female and male clusters. At least three juvenile instars are represented in these assemblages. The dimensions of illustrated specimens are given in Table 2.