The whale barnacle Cryptolepas rhachianecti (Cirripedia: Coronulidae), a phoront of the grey whale Eschrichtius robustus (Cetacea: Eschrichtiidae), from a sandy beach in The Netherlands
Author
Bosselaers, Mark
Author
Collareta, Alberto
text
Zootaxa
2016
4154
3
331
338
journal article
10.11646/zootaxa.4154.3.8
c98e993b-5176-42a5-8aa7-c4bda5dd3c5c
1175-5326
272173
6C09E4D7-4EC8-4398-B171-96060ACAD357
Cryptolepas rhachianecti
Dall, 1872
Fig. 2
Cryptolepas rhachianecti
Dall, 1872
: 300
Cryptolepas rhachianectis
Gruvel, 1903
: 153
, pl. 2, figs. 4–10; pl. 3, figs. 10-11
Material examined.
NHG
27
0 0 1, left latus or carinolatus collected from beach deposits in
Zoutelande
(
Walcheren
,
The Netherlands
), at the mouth of the
River Scheldt.
Description and remarks.
The size and aspect of this isolated left lateral or carinolateral compartment matches well the descriptions of the hard parts of
Cryptolepas rhachianecti
given by
Pilsbry (1916)
,
Zullo (1961
,
1969
),
Davis (1972)
,
Ross & Frick (2011)
and
Hayashi (2012)
. In particular, NHG 27 0 0 1 strikingly recalls the illustration of a cylinder-shaped specimen of
C. rhachanecti
, with very short external ribs, provided by
Pilsbry (1916, pl. 66, figs. 2, 2a)
.
Pilsbry (1916)
described
C. rhachianecti
as follows: "[
C. rhachianecti
] differs [from
Cetopirus complanatus
and
Coronula
spp.] by lacking terminal flanges uniting the radial lamellae [i.e., the external ribs, or buttresses] into a solid outer wall, though there is sometimes a suggestive approach to this structure. [...] four to six ribs are seen on each compartment above. These ribs are denticulate along both sides. [...] They are finely striated vertically and crenulated at the basal edges. [...] The radii are as thick as the compartments [...]. The sheath is transversely grooved, a little shorter than the body-chamber, and its lower margin is not overhanging or prominent". Most of these characters can be clearly observed in NHG 27 0 0 1 (
Fig. 2
) and, on the whole, they allow us to unambiguously attribute NHG 27 0 0 1 to
C. rhachianecti
. Nevertheless, the specimen from Zoutelande appears slightly damaged, and the external ribs are moderately eroded and worn (likely as a consequence of mechanical degradation in the current beach environment). Whereas extant coronulid shells are typically whitecoloured and rather translucent, the specimen here studied is brownish and strongly opaque; as such, it was likely affected by some process of early fossilization (e.g. recrystalisation or permineralisation).