Evolution of the hectocotylus in Sepiolinae (Cephalopoda: Sepiolidae) and description of four new genera
Author
Bello, Giambattista
text
European Journal of Taxonomy
2020
2020-05-29
655
1
53
journal article
21713
10.5852/ejt.2020.655
fadee126-7da7-47d9-b9ac-973697ecf9f5
2118-9773
3888797
0042EFAE-2E4F-444B-AFB9-E321D16116E8
Eumandya
gen. nov.
urn:lsid:zoobank.org:act:
6FB7B832-3CFA-4914-842A-A526390BFCFD
Fig. 9
(the generic name used in the caption is the former one)
Type
species
Euprymna pardalota
Reid, 2011
, here designated.
Diagnosis
Sepiolinae
with fins rounded; their length about half mantle length.Arm suckers in two longitudinal rows. Tentacle club suckers in 6 to 14 longitudinal rows. Mantle-head occipital band broad, extending over the ocular globes. A pair of kidney-shaped photophores on ventral surface of ink-sac. Gladius absent. Ventral mantle margin faintly sinuate or with slightly deep funnel indentation. Hectocotylus (male left arm I) bipartite: proximal part, occupying ¾ to ½ of arm, with regular suckers, except for pedicel of 3
rd
sucker in ventral row lengthened, papilla-like (may bear vestigial sucker at its tip); distalmost part, occupying ⅓ to ½ of arm distally, with lengthened columnar sucker pedicels, closely packed longitudinally bearing reduced suckers and not connected with each other by any web. Female bursa copulatrix pouch-like.
Included species
Euprymna pardalota
(
Reid, 2011
)
gen. et comb. nov.
,
E. parva
(Sasaki, 1914)
gen. et comb. nov.
and
E. phenax
(Voss, 1962)
gen. et com. nov.
Etymology
This genus is named in honour of Amanda Reid (Australian Museum Research Institute, Sydney) for her outstanding contribution in the field of cephalopod taxonomy, including
Sepiolinae
. The generic name is derived by the combination of Mandy, the diminutive name by which she is known to her friends and colleagues, and the prefix
Eu
- in order to keep the assonance with the sister genus
Euprymna
. Gender feminine.
Discussion of affinities
The members of
Eumandya
gen. nov.
, namely
parva
,
pardalota
and
phenax
, were formerly assigned to
Euprymna
because of the palisaded distalmost part of the hectocotylus, which, despite minor differences, is a unique feature of the clade (
Eumandya
gen. nov.
,
Euprymna
). In addition to the readily evident difference in number of longitudinal sucker rows on arms, i.e., biseriate arrangement in
Eumandya
gen. nov.
vs tetraseriate arrangement in
Euprymna
, minor differences include the lack of well-developed fleshy caps on the columnar suckers and the lack of lengthwise connections between the ventral columnar pedicels in the former genus. An additional sign of possible hectocotylian primordiality in
Eumandya
gen. nov.
is the presence of one-single-modified-stalk in the copulatory apparatus; in most
Euprymna
s.s.
species it is composed of two or three papillae.
Remarks
Eumandya pardalota
gen. et comb. nov.
and
E. parva
gen. et comb. nov.
are deemed sister species (Reid, pers. com.;
Sanchez
et al.
2019
). The latter authors rightly removed
parva
from
Sepiola
, as previously understood, based on both morphological features and genetic analyses (
Sanchez
et al.
2019
). Their decision is congruous with both the absence of modified dorsal sucker pedicels in the formation of the copulatory apparatus of the hectocotylus and the presence of palisaded suckers in its distalmost part, which characters do not pertain to
Sepiola
. The distribution of the members of
Eumandya
gen. nov.
is limited to the eastern Indian-western Pacific Oceans.