Paleogene Verrucidae (Cirripedia: Verrucomorpha) of North America, with descriptions of three new species
Author
Perreault, Ray T.
Author
Buckeridge, John S.
text
Zootaxa
2019
2019-12-18
4712
1
34
50
journal article
24558
10.11646/zootaxa.4712.1.2
19829187-393b-46c5-8e83-c132a5742fb3
1175-5326
3586816
6C18DE3D-8B51-473D-B528-98337BF5730E
Genus
Verruca
Schumacher, 1817
Verruca
Schumacher, 1817: 35
.–
Darwin, 1854: 496
.–
Zevina, 1987b: 1812
.–
Newman & Hessler, 1989: 268
.–
Buckeridge, 1994: 90
.–
1997: 128
.
Verruca
“Section B”
Pilsbry, 1916: 23
.
Verruca
(
Verruca
)
.–
Newman, Zullo & Withers, 1969
: R281.–
Foster, 1978: 68
.
Euverruca
Broch, 1924: 63
.
Type
.
Lepas stroemia
Müller, 1776: 251
, OD.
Diagnosis.
Verrucids with shell form depressed; apices of rostrum and carina marginal; operculum parallel to base (
Buckeridge, 1997: 128
).
Discussion.
Verruca
, as presently defined (
Buckeridge, 1997
), is a convenience group comprising those verrucids with the operculum nearly parallel to the base, and marginal apices on the rostrum and the carina. Former subgenera of
Verruca
sensu lato
were elevated to full generic rank by
Zevina (1987a
, b). This classification has been accepted by later workers.
Young (1998)
named three more genera based on shell characters. Species of this genus, as presently restricted, fall into several lineages, which eventually may be separated into other genera (
Buckeridge, 1997
). The lineage that includes depressed shells, such as
Verruca stroemia
(typical
Verruca
), extends from the Late Cretaceous (late Maastrichtian;
Gale, 2014
) through the Recent, and comprises predominantly littoral species. The earliest records of this lineage occur in the Cretaceous of
Western Australia
with
V. tasmanica tasmanica
Buckeridge, 1983
and now includes the taxa described in this paper. All of the species in this lineage have a fixed scutum with a well-formed adductor plate. In some species, such as
Verruca stroemia
,
Verruca jago
Buckeridge, 1997
and
Verruca reunioni
Foster & Buckeridge, 1995
, this plate extends to produce a rounded myophore. However, although all of the new species described herein possess a clear adductor plate, none have a definitive myophore.
Buckeridge (1997: 130)
noted that fine, regularly spaced punctae extending from the exterior through the wall plates and opercula to the interior surface also characterize some members of this lineage. In extant species, such as
Verruca stroemia
,
Verruca laevigata
G.B.
Sowerby, 1827
and
Verruca jago
, these punctae contain chitin, and
Buckeridge (1997)
considered it likely that this would have mitigated shell loss. In shallow, aerated coastal waters, where localized conditions could approach a pH of less than 7, this would have been advantageous in helping to preserve shell integrity. Punctae have also been observed in some fossil verrucids, e.g.
Verruca tasmanica
,
Verruca digitali
Buckeridge in
Buckeridge & Finger, 2001
(Miocene, California) and
Verruca viteus
Buckeridge, in
Buckeridge, Lee & Robinson, 2014
(Oligocene,
New Zealand
). Although they have not been recorded from
Verruca alabamensis
sp. nov.
(this paper),
V. rocana
Steinmann, 1921
(Palaeocene,
Argentina
) and
Verruca sauria
Buckeridge, 2011
(Late Cretaceous,
New Zealand
), their apparent absence may be due to diagenetic processes in some cases. They are apparently absent in
V. alabamensis
sp. nov.
, and as the specimens are well preserved, punctae probably did not develop in this taxon. Nonetheless, the presence of punctae is a useful diagnostic feature for members of this lineage.
Occurrence.
Upper Cretaceous to Recent, cosmopolitan. Most known fossil species are shallow water. Living species may be found from the intertidal zone to
620 m
depth.