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
sp. 2
[of
Morais & Coimbra 2017
,
Brazil
]
(
Figures 15A–I
,
16F–I
)
2017
Bairdoppilata
sp. 2
: Morais & Coimbra, fig. 3E.
Material Examined.
Five specimens from Saco do Francisco,
Brazil
.
Dimensions:
Specimen 3991F, LVL
0.974 mm
, LVH
0.672 mm
. Specimen 3988F, RVL 0.91, RVH 0.509.
Esophageal Valve:
The plate is flat, broadly wedge-shaped, and furnished with about 14 evenly spaced triangular teeth (
Fig. 16G
). The scroll-like indentations on the anterior edges are well marked. The bracket consists of two curving triangular walls arranged in a V, with conspicuous tubercles along their anterior ends. The braces have thick shafts and rather short, blunt aprons (
Fig. 16H
).
Anatomical Remarks:
In lateral view the dorsal margin of the carapace arches to unusually great height, the posterior end is not caudate, and the surface is entirely smooth (
Figs. 15A–B, H
).
The distal antennal claws are short, saber-like and sharply pointed, with the anterodistal claw being slightly thinner than the main claw (
Figs 15D–E
). The fused claw is smooth. The eye is unusually large and dark red (
Fig. 15A, F
).
Taxonomic Remarks:
Morais and Coimbra (2017)
collected empty valves (interpreted as allochthonous) of
B
. sp.
2 in
turf algae of rocky shores immediately below low tide (
1–3m
) in
Santa Catarina State
, southern
Brazil
. They pointed out, correctly, that the taxonomic composition of phytal assemblages of rocky shores is poorly known, echoing similar comments by
Maddocks (2013)
. Then, they characterized
Bairdoppilata
as a “shelf genus, which lives mainly on sandy sediments,” and they expressed surprise at finding these valves captured by algal turf. This illustrates a familiar paleoecological dilemma: It is easy to equate the site of collection with the habitat in life, forgetting that most species are known only from subfossil valves collected in sea-floor sediments, after post-mortem transport and mixing by sedimentary and taphonomic processes.