Late Cenozoic Ostracodes — Holden 
21 
Fig. 13. Paracytheridea sp. a-b, Specimen usnm 648743; a, lateral view of left valve; b, dorsal view. 
wide faint sulcus, modified holamphidont 
hinge; adductor muscle scar pattern of at least 
six scars. 
description: Carapace very inflated, widely 
but faintly sulcate; dorsal margin straight, sub- 
parallel to almost straight ventral margin, both 
slightly converging posteriorly; short postero- 
dorsal margin straight in left valve, concave in 
right valve ; posteroventral margin rounded, ex- 
tended, with five or six denticulations ; anterior 
margin broadly rounded, flattened dorsally, 
finely denticulate in ventral part; left valve 
overlapping right valve along posterodorsum, 
at anterodorsal angle, and at ventral inturned 
area; surface of carapace mostly smooth, sparsely 
covered with faint pits; narrow ventral ridges 
continuing partially up anterolateral surface. 
Hinge modified holamphidont: anterior tooth 
of right valve small, with subjacent entire 
socket; median bar smooth; posterior element 
elongate, notched twice below. 
Adductor muscle scar pattern basically six 
smaller scars on posterior side of small pit: top 
scar elongate, or crescent shaped, five circular 
scars below; antennal scar pattern a triangle of 
three equal scars on anterior side of pit; two 
elongate mandibular scars below antennal 
group, four or more above adductor group. 
Radial pore canals straight, simple, apparently 
very dense (not illustrated); no vestibules pres- 
ent ; heavy selvage in left valve with correspond- 
ing continuous groove in right valve. Interior 
heavily pitted. 
dimensions: 
SPECIMEN 
LENGTH 
WIDTH 
HEIGHT 
Holotype usnm 648744 
(entire) T-12 
0.83 
0.43 
0.43 
Para type sdnh 1042 
(right valve) T-12 
0.83 
0.22 
0.42 
Paratype usnm 648745 
(right valve) T-12 
0.80 
0.22 
0.42 
distribution: As fossils from T-ll (1 
valve) and T-12 (9 valves; 2 entire). 
discussion: The 12 specimens available are 
poorly preserved and details of the marginal 
areas are only barely visible using clearing oil 
and transmitted light. Figure 14 c shows only 
a few of the almost obliterated, apparently 
abundant radial pore canals. The large marginal 
pits are exterior, not interior, as might be sug- 
gested in the figure. 
