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By JACK D. MOUNT¹
ABSTRACT: Neadmete schwartzi, a new species of gastropod belonging to the family Cancellariidae, is described from the Upper Pliocene Fernando Formation near Newport Bay, Orange County, California.
During February, 1967, earth moving equipment on the east bluff of upper Newport Bay, Orange County,
California, uncovered a highly fossiliferous portion of the lower part of the Fernando Formation. This locality remained exposed until
August of the same year when further construction destroyed it. Between these months extensive collecting at the exposure by me and my
associates yielded an interesting fauna of over 200 species of larger invertebrates characterized by Nuculana fossa (Baird,
1863), Patinopecten healeyi (Arnold, 1906), Pecten hemphilli Dall, 1879, Glycymeris grewingki Dall, 1909,
Exiloidea rectirostris hertleini Bentson, 1940, Neptunea tabulata colmaensis (Martin, 1914), Boreotrophon raymondi
(Moody, 1916) and Mya truncata Linné, 1758. This assemblage suggests a Late Pliocene age based on a two-fold division of
the Pliocene of California (Vedder, 1960).
While studying the material several new species of
mollusks were noted. One of these belongs to the genus Neadmete Habe, 1961, which was only recently recognized in the west
American fauna (Kanakoff and McLean, 1966). This new species is described herein.
References to the
Los Angeles County Museum of Natural History, Section of Invertebrate Paleontology are hereafter abbreviated as LACMIP.
I am grateful for the assistance of the following persons. Dr. Robert F. Meade, California State College at Los Angeles, and Dr. James H. McLean, Los Angeles County Museum of Natural History, gave helpful advice and critically reviewed the manuscript. Mr. Jack Schwartz, Mr. Boris Savic and Mr. and Mrs. F. L. Grouard aided in collecting the type.material. Photographs are by Mr. Louis W. Kundrath and Mr. James W. Shuttleworth of Kundrath Studio of Photography, Baldwin Park, California.
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Family Cancellariidae Gray, 1853
Genus Neadmete Habe, 1961
Neadmete schwartzi new species
Figure 1
Diagnosis: Shell relatively large; whorls 8, evenly convex, weakly tabulate; 16 spiral ribs on
body whorl; outer lip reflected.
Description: Shell relatively large for genus, long, slender, fusiform; spire elevated. Whorls 8,
moderately inflated, evenly convex, weakly tabulate on early whorls becoming obsolete on penultimate and body whorls. Nucleus simple,
smooth, whorls 2. Axial sculpture of approximately 16 low, rounded ribs, becoming obsolete on last four whorls. Spiral sculpture of
low, narrow, rounded ribs, 3 on postnuclear whorls and 16 on body whorl; with single smaller rib intercalated between major ribs on the
apical whorls and the first nine ribs of the body whorl; interspaces slightly wider than ribs. Sutures moderately impressed. Aperture
subeliptical, approximately one half the height of the shell; outer lip smooth, thin, slightly reflected, with 15 internal spiral
lines; canal short and shallow. Columella long, straight, with two folds and eight plicae formed by extension of primary spiral ribbing.
Type Material: Holotype, LACMIP 1779. Four paratypes: LACMIP 1780; California Academy of Sciences
(CAS), Department of Geology type collection 13203; University of California at Los Angeles (UCLA), Department of Geology type
collection 47313; and collection of Jack D. Mount (JDM) 106². Measurements for the type specimens are listed in Table 1.
Type Locality: LACMIP locality 471; 33° 38' 21" N, 117' 53° 02" W; in a 6 foot thick lens
of sandy cobble conglomerate which occurs approximately 425 feet stratigraphically above the base of the formation. At the present time
it is located under the residence at 2161 Vista Entrada, Newport Beach, California.
Age and Formation: Late Pliocene, Fernando Formation.
Discussion: Neadmete schwartzi is nearest to the Recent N. circumcincta (Dall,
1873:59) but differs from that species principally in the larger size, more evenly convex, less tabulate whorls, more spiral ribs and
in the presence of the reflected outer lip. N. circumcincta is recorded from Alaska, with a specimen in the Los Angeles County
Museum of Natural History from Hope Island, off the northern end of Vancouver Island, British Columbia. N. sutherlandi Kanakoff
and McLean, (1966:4) from the Lomita Marl (Plio-Pleistocene) of Los Angeles County, California, is the only other fossil species of
Neadmete and it is readily distinguished from N. schwartzi by its larger size, more pronounced tabulation, and smaller
number of spiral ribs.
Etymology: This new species is named for Mr. Jack Schwartz, who collected the holotype, in
recognition of his contributions to the mineralogy
of California.
TABLE 1. Measurements (in mm) of the type specimens | |||
| Specimen no. | Height | Diameter | Height of Aperture |
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| LACMIP 1779 | 35.6 | 16.9 | 16.8 |
| LACMIP 1780 | 28.2 | 14.8 | 13.3 |
| CAS 13203 | 35.3 | 17.9 | 16.5 |
| UCLA 47313 | 33.7 | 17.1 | 15.7 |
| JDM 106² | 31.3 | 15.7 | 15.1 |
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LITERATURE CITED
DALL, W.H. 1873. Preliminary descriptions of new species of Mollusca from the coast of Alaska, with notes on some rare
forms. Proc. Calif. Acad. Sci., 5: 57-62, pl. 2.
KANAKOFF, G. P., AND J. H. McLEAN. 1966. Recognition of the cancellariid genus Neadmete Habe, 1961, in the west American
fauna, with description of a new species from the Lomita Marl of Los Angeles County, California. Los Angeles County Mus., Cont. in Sci.,
116: 1-6.
VEDDER, J. G. 1960. Previously unreported Pliocene Mollusca from the southeastern Los Angeles basin, in Short papers in the
geological sciences. U. S. Geol. Survey Prof. Paper 400-B, B326-B328.
Accepted for publication October 31, 1969.
¹Department of Geology, California State College, Los Angeles, 90032.
²Paratype specimen now in the Type Collection of the Department of Earth Sciences, University of California, Riverside.
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