Systematics and preliminary phylogeny of Bornellidae (Mollusca: Nudibranchia: Dendronotina) based on morphological characters with description of four new species
Author
Pola, Marta
Author
Rudman, William B.
Author
Gosliner, Terrence M.
text
Zootaxa
2009
1975
1
57
journal article
10.5281/zenodo.185130
6ea2d9a4-cff3-42df-ad0c-cfbc6f9034ed
1175-5326
185130
Bornella excepta
Bergh,
1884
Bornella excepta
Bergh,
1884
:
34
–43, Pl. VII, figs
13–22
., Pl. VIII, figs
1–13
;
Bergh,
1902
:
202
–204, Pl. III, figs
4–5
;
Bergh,
1905
:
220
–221, Pl. XIX, figs
25–27
.
Material examined:
No specimens have been recognized as this species since
Bergh (
1905
)
.
Remarks:
Bergh (
1884
)
described
Bornella excepta
from a
60 mm
preserved specimen, from Arafura Sea, in the Pacific Ocean. The color of the animal alive is unknown and no
type
specimen exists. Nevertheless, the author gave a fully detailed description of the external morphology and the internal anatomy. With such a good description, the species should be easily recognizable within the genus.
Eliot (
1904
)
tentatively identified a specimen of
Bornella
from the east coast of
Zanzibar
as this species, but there is no way of confirming its identity. There are some similarities between
B. excepta
and
B. hermanni
, but we consider the similarities to be outweighed by the following differences: the number of lamellae on the rhinophore is about
20 in
B. hermanni
and between
40
and
50 in
B. excepta
;
B. hermanni
has three pairs of dorsolateral processes with three gills per dorsolateral process while
B. excepta
has five pairs of dorsolateral processes with four gills: also the anterior digestive glands of
B. hermanni
have branches entering the rhinophore sheaths while they do not in
B
.
excepta
and, finally, the number of ovotestis follicles is different, from around four in
B
.
hermanni
to nine in
B. excepta
. The shape of the penis and its associated spines, as illustrated by
Bergh (
1884
, Pl.
17
, figs
18–22
)
is also very similar. There are also similarities in the shape of the dorsolateral processes and the penial armature to
B. dotoides
sp. nov.
but the dentition on the central radular tooth of
B. excepta
appears much coarser. Until new specimens are found which are a closer match to the original description, we have no way of comparing
B. excepta
to any better known species and so must tentatively retain it as a different and valid species within the genus.