Late Cenozoic Ostracodes — Holden 
TABLE 3 
Dimensions of Bairdia kauaiensis N. sp. 
9 
SPECIMEN 
LENGTH 
WIDTH 
HEIGHT 
Holotype usnm 648719 (entire $) T-12 
1.20 
0.67 
0.78 
Paratype sdnh 1026 (right valve $ ) T-12 
1.20 
0.27 
0.70 
Paratype USNM 648720 (right valve $ ) T-12 
1.26 
0.30 
0.67 
Paratype USNM 648721 (right valve $ ) S-23 
1.10 
0.28 
0.65 
Paratype sdnh 1027 (penultimate left valve) T-12 
0.94 
0.30 
0.58 
Paratype sdnh 1028 (3d from last left valve) T-12 
0.68 
0.23 
0.41 
Paratype sdnh 1029 (4th from last left valve) T-12 
0.47 
0.13 
0.28 
Paratype sdnh 1030 (5th from last left valve) T-12 
0.37 
0.11 
0.22 
Paratype usnm 648722 (left valve $ ) T-12 
1.23 
0.45 
0.80 
dimensions: See Table 3. 
served population is 
easily grouped into five 
distribution: As fossils from T-l (8 valves; 
molt stages. General shape and inflation, char- 
2 entire), T-2 (10 valves), T-4 (4 valves; 1 
acteristic of mature specimens, 
is also consistent 
entire), T-7 (4 valves; 2 entire), T-8 (1 en- 
to the fifth-from-last instar. 
tire), T-ll (21 valves; 1 entire), T-12 (82 
The large adductor 
muscle 
scar pattern has 
valves; 7 entire), AR (6 valves; 4 entire), and 
diagnostic reliability, 
with a 
rectangular mid- 
S-23 (10 valves). Reported by Brady (1880) 
near Australia at Torres Strait, Humboldt Bay, 
Hawaiian Islands, Booby Island (10° 36'S, 
141° 55'E), and by Brady (1890) at New 
Caledonia and Fiji. In the East Pacific, found 
living at Clipperton Island at CL (2 entire), 
and the Hawaiian Islands at T-13 (10 valves). 
die scar surrounded by about five other scars 
and two aligned elongate scars below. Using the 
adductor muscle scar pattern alone, obvious dif- 
ferences can be seen between B. hanaumaensis, 
B. attenuata (the latter having a very small ad- 
ductor muscle scar group), and the present 
species. 
discussion: Bairdia kauaiensis n. sp. and B. 
amygdaloides of Brady, 1880 are conspecific, 
differing only in that the fossils show finer pit- 
ting than mentioned by Brady. The type speci- 
men of B. amygdaloides from Australia de- 
scribed by Brady in 1866 appears to be a form 
altogether different from the present forms and 
those identified with B. amygdaloides by Brady 
in 1880. The type of B. amygdaloides is only 
0.78 mm long, or about the length of the sec- 
ond- to third-from-last instar of the Hawaiian 
specimens. Brady (1866:364) mentions that it 
may be a young; however, it does not bear any 
resemblances to the young of the new species. 
Bairdia kauaiensis n. sp. is one of the most 
commonly occurring ostracodes from the 
drowned terraces in the Hawaiian Islands. It is 
present in significant numbers at all stations, 
including the Recent T-13, but it is absent 
from the Recent lagoonal assemblage at HA, 
where B. hanaumaensis is common and B. at- 
The species is named for the island of Kauai, 
in the Hawaiian Islands. 
Bairdia sp. 
Figs. 4 a-d 
description: Carapace smooth; highly in- 
flated centroventrally. In lateral view: dorsal 
margin evenly rounded; dorsoanterior straight; 
dorsoposterior straight to slightly concave; ven- 
tral margin gently concave ; ventroanterior 
bluntly rounded ; ventroposterior gently con- 
cave; valves unequal; caudal process in right 
valve pointed, ventrodorsally concave ; left valve 
with poorly developed caudal process. In dorsal 
view: slightly concave between bulbous center 
and blunt thick ends. 
Adductor muscle scar pattern small, near 
center; of about 7 or 8 smaller scars; vestibules 
of moderate size ; normal and radial pore canals 
unobserved. 
dimensions : 
tenuata is rare. 
Little variation occurs in this species except 
for sexual dimorphism in mature specimens, 
with the supposed males being taller. The pre- 
SPECIMEN 
usnm 648723 
(entire $ ) AR 
sdnh 1031 
(left valve $ ) AR 
LENGTH HEIGHT WIDTH 
1.10 0.70 0.70 
1.10 0.75 0.40 
