Post-extinction survivor fauna from the lowermost Famennian of eastern North America
Author
Day, Jed
Author
Over, D. Jeffrey
text
Acta Palaeontologica Polonica
2002
2002-12-31
47
2
189
202
journal article
300554
10.5281/zenodo.13174914
c2009942-e0f2-4d16-b1ef-026cefdf1680
1732-2421
13174914
Cyrtospirifer hornellensis
Greiner, 1957
Fig. 4H, I
.
Cyrtospirifer hornellensis
;
Greiner 1957: 28–29
, pl. 7: 1–5, 6 (not dorsal valve specimen on right−hand part of image of Yale Peabody Museum number 19435B), and 7.
Material
.—Figured specimens
NYSM
15691 and
NYSM
15692.
Remarks
.—The available specimens are consistent with the species as described by
Greiner (1957: 29)
. It must be pointed out that
Greiner (1957)
illustrated at least two distinct genera under the name
C. hornellensis
. One of the two dorsal valves (his “larger, presumably gerontic, individual” of Yale Peabody Museum number 19435B) illustrated in his pl. 7 (fig. 6, right−hand specimen) represents a new genus, which will be described (Ma and Day personal communication 2001) from the lower Famennian of South
China
.
Cyrtospirifer hornellensis
is about half the size (width), has a narrower sinus and fewer flank plications, and lacks the medial groove on the dorsal fold of the much larger
Cyrtospirifer sulcifer
(
Hall and Clarke, 1894
)
. That form serves as the nominal species for the lowest Famennian
C. sulcifer
Assemblage Zone
of
Dutro (1981: 80
, figs. 2, 7). As defined, that zone spans the interval of the Canadaway Group, immediately above the Java Formation of
New York
.
Cyrtospirifer sulcifer
(
Hall and Clarke, 1894
)
is not a true
Cyrtospirifer
and is considered here a species of
Pripyatispirifer
Pushkin (1996)
. According to
Greiner (1957)
his illustrated specimens of
C. hornellensis
were collected
140 feet
(42.6 meters) below the top of the upper Frasnian Wiscoy Formation (now Java Formation) and overlying deposits of the lower Famennian “Casaseraga formation” (= Caneadea Formation of the modern nomenclature). Greiner portrays its upper range (see his fig. 4) as somewhere high in the lower Famennian. Thus far, our material represents its lowest Famennian occurrence directly associated with Lower
Pa. triangularis
Zone
conodonts in the upper part of the Hanover Shale of eastern North America.