Geology and Paleontology of Canal Zone and Adjoining ... - USGS

GASTROPODS: EULIMIDAE, MARGINELLIDAE TO HELMINTHOGLYPTIDAE 395
like any known species of Cryoturris; in fact, the
coarsely frosted spiral sculpture suggests species of
Kurtziella s.s.
Occurrence: Lower part of Gatun formation (middle
Miocene), locality 138d.
Genus Nannodiella Ball
Dall, U.S. Natl. Mus. Proc., v. 56, p. 59, 1919.
Type (orthotype): Nannodiella nana (Dall) [Philberta (Nan-
nodiella) nana Dall], living, Gulf of California.
The extraordinarily large anal sinus of Nannodiella
is unique among American mangeline turrids. The
aperture is armed with denticles of varying strength
or unarmed. The genus has been found in the lower
Miocene of Florida; the middle Miocene of Trinidad,
the Dominican Republic, Jamaica, the Caribbean coas­
tal area of Panama, and Florida; the upper Miocene
of the Bocas del Toro area, Panama, Florida, and
Ecuador; and the Pliocene of Ecuador and Florida;
and is living in western Atlantic and eastern Pacific
waters, and also, according to Powell (1966, p. 115)
in the western Pacific Ocean. Of the three species,
other than the type species, assigned, or doubtfully
assigned, by Dall (1919, p. 60-61) to Nannodiella, only
Philbertia (N annodiell'O) fratertmlis is acceptable as
Nannodiella.
Nannodiella rintriada (Mansfield)
Plate 60, figure 10; plate 64, figure 7
Glyphostoma amicta rintriada Mansfield, U.S. Natl. Mus. Proc., v.
66, art. 22, p. 27, pi. 4, figs. 2, 3, 1925 (Miocene, Trinidad).
Very small, slender, anal fascicle constricted. Pro-
toconch 4-whorled, tip acute and minute, last whorl
to last 11/2 whorls carinate below middle of whorl. End
marked by appearance of sculpture. First post-proto-
conch whorl carinate, succeeding whorls progressively
less carinate. Post-protoconch whorls sculptured with
10 to 13 (generally 10 to 12) narrow axial ribs, pinched
on anal fascicle, but continuing to suture. Primary
spiral sculpture consisting of 2 subequal threads below
anal fascicle on spire whorls (exceptionally 3 on penult
whorl), 3 on body whorl, overriding ribs and slightly
swollen on their crests. Anal fascicle bearing 4 to 6
very narrow threads; wider, more closely spaced
threads on lower part of body whorl. Body whorl swol­
len adjoining outer lip. Anal sinus extraordinarily
large for size of shell and aperture, apex and upper
limb heavily bordered. Aperture short. Outer and
columellar lips bearing moderately strong denticles.
Siphonal canal very short, barely emarginate; sipho-
nal fascicle barely inflated.
Height 4.5 mm, diameter 1.9 mm (figured specimen).
Type material: Lectotype, herewith designated,
larger of 2 syntypes, USNM 352642.
Type locality: USGS 8302, a mile south of Brasso
railway station, Trinidad, flood-wash from stream
bank, Brasso formation.
The middle part of the Gatun formation yielded 32
specimens all except seven from the rich locality 147b
of this small mangeline. The axial ribs on the single
specimen from the upper part of the formation are
more subdued than on the other shells.
Nannodiella rintriada is more slender than N. amicta
(Guppy) (Woodring, 1928, p. 195, pi. 8, fig. 12), a
middle Miocene Jamaican species; its primary spiral
threads are of subequal strength; and its apertural
denticles are stronger. The type material of N. rin­
triada, like that of 30 other species and subspecies
named by Mansfield, was collected from float along
Caparo Eiver above Brasso railway station: a con­
venient collecting locality, but a poor type locality.
Eight specimens are in an outcrop collection from
Mayo River (USGS 21234, Globorotalia fohsi robusta
zone) and seven in an outcrop collection from Cas­
cade River (USGS 19856, upper part of Globorotalia
fohsi zone s.l.), both deposited by H. G. Kugler. The
shells from locality 21234 have heavier apertural den­
ticles than Gatun shells, whereas those from locality
19856 have weaker denticles than those from the Gatun
formation.
Occurrence: Middle and upper parts of Gatun for­
mation (middle Miocene). Middle part, eastern area,
localities 139c, 147b, 147g, 155, 155c; western area,
locality 161. Upper part, eastern area, locality 163.
Early middle Miocene part of Brasso formation, Trini­
dad.
Nannodiella cf. N. melanitica (Dall)
Two specimens found at locality 139b represent a
second species of Nannodiella, although N. rintriada
occurs in another collection (139c) from the same
locality in strata near the base of the middle part of
the Gatun formation. It is smaller (height 3.5 mm)
and more slender than N. rintriada and its sculpture
is more subdued. The axial ribs are narrower and
more numerous (14 or 16 on penult whorl), and the
primary spiral threads are narrower. Both shells are
somewhat chalky and cannot be cleaned properly for
photographing.
This unnamed species has stronger axial and spiral
sculpture than Mangilia melanitica Dall (in Dall and
Simpson, 1901, p. 390, pi. 58, fig. 10), which ranges
from Cape Hatteras to the eastern Gulf of Mexico
and Puerto Rico.
Occurrence: Middle part of Gatun formation (mid­
dle Miocene), eastern area, locality 139b.