Description of Kashmirobroscus gen. nov. with two new species from the Northwest Himalaya, and remarks on the East Asian genus Eobroscus Kryzhanovskij, 1951 (Coleoptera: Carabidae: Broscini)
Author
Schmidt, Joachim
Lindenstrasse 31, 18211 Admannshagen, Germany;
Author
Wrase, David W.
Dunckerstrasse 78, 10437 Berlin, Germany;
Author
Sciaky, Riccardo
Via Fiamma 13, 20129 Milano, Italy
text
Journal of Natural History
2013
J. Nat. Hist.
2013-09-03
47
41 - 42
2671
2689
http://dx.doi.org/10.1080/00222933.2013.791952
journal article
55814
10.1080/00222933.2013.791952
857d6372-de50-463d-8471-717e72bdd3ba
1464-5262
4608237
1775013D-FE87-41CA-87AF-D730E809331B
Eobroscus masumotoi
Morita, 1990
TAIWAN
:
Alishan
[locus typicus],
2400 m
,
17–26 June 1995
,
Dalihod
leg. (
1 female
, cWR); same data but:
P. Moravec
leg. (
1 female
, cSCI)
.
Remarks on new synonymies
The genus
Eobroscus
Kryzhanovskij, 1951
was described for
Broscus lutshniki
, a species from the Siberian Far East and
Japan
. More than 30 years later a second species,
E bhutanensis
Morvan, 1982
was described from
Bhutan
. Still later,
Morita (1990)
, when describing a third species (
E. masumotoi
from Taiwan) created the subgenus
Orobroscus
for the two species
E. bhutanensis
and
E. masumotoi
. Finally, in 1995 the same author described a third species of that subgenus,
E. uenoi
Morita, 1995
, from
Vietnam
. The distinguishing characters of
Orobroscus
mentioned by
Morita (1990: 159)
were:
(i) the occurrence of two setae at each side of the last abdominal sternite of the male,
(ii) the presence of adhesive hairs on the proximal two (instead of three) protarsomeres in the male, and
(iii) the lack of dorsal strigosity of the onychium.
We had the opportunity to examine additional
Eobroscus
material covering the whole geographical distribution of that genus and all the known species. As a result we observed the great similarity of the three taxa attributed to
Orobroscus
as well as the remarkable variability of the characters used for the separation of the latter taxon. For example, concerning the setosity of the last abdominal sternite we observed that in both the species,
E. masumotoi
and
E. lutshniki
, some male specimens had a single seta on one side but two on the opposite side. In most of the
E. bhutanensis
males we found two pairs of setae, but in a specimen from
Vietnam
we found only one pair. Also the
holotype
specimen of
E. uenoi
Morita, 1995
, bears a single pair of setae at the apical margin of the last abdominal sternite. Moreover, we found an
E. lutshniki
female specimen from Sakhalin that bears three setae on the right and two on the left side. Based on these observations we conclude that within the genus
Eobroscus
the number of setae developed at the apical margin of the last abdominal sternite is not a speciesspecific constant. For this reason, abdominal setation seems inappropriate to be used as a differential character to define natural lineages within
Eobroscus
. This conclusion was already reached by
Morita (1995: 11)
in the paper with the description of
E. uenoi
Morita, 1995
; however, the author still maintained the validity of
Orobroscus
.
Concerning protarsal adhesive vestiture of males we confirm the observation of
Morita (1990)
who found adhesive vestiture on the proximal three tarsomeres of
E. lutshniki
(
Figure 4D
) and on the proximal two tarsomeres of
E. bhutanensis
(
Figure 4G
) and of
E. masumotoi
. However, as a result of a comprehensive phylogenetic analysis of the tribe
Broscini
Roig-Juñent (2000)
showed that this character has several parallel gains and losses, and it is therefore of low phylogenetic value (zero in the cladistic analysis of
Roig-Juñent 2000
). Species of the same genus and even of the same subgenus have or lack this structure. Those conditions
Roig-Juñent (2000)
found also regarding the mesotarsal adhesive vestiture. The different extent of adhesive vestiture on male mesotarsomeres in
Eobroscus
species is shown in
Figure 4E
(
E. lutshniki
, adhesive vestiture covers approx. 75% of the ventral surface of tarsomere 2) and
Figure 4H
(
E. bhutanensis
, adhesive vestiture covers less than 50% of the ventral surface of tarsomere 2).
Concerning the surface morphology of the onychium we found traces of dorsal longitudinal strigosity also in
E. bhutanensis
(see
Figure 4I
) and in
E. masumotoi
. This is in contrast to the statement of
Morita (1990: 156)
that members of
Orobroscus
have a smooth onychium dorsally. It is true that strigosity of the onychium is much more markedly developed in
E. lutshniki
(
Figure 4F
).
In summary, we state that separation of a subgenus
Orobroscus
as defined by
Morita (1990)
is highly questionable. Therefore, we propose
Orobroscus
Morita, 1990
as a junior synonym of
Eobroscus
Kryzhanovskij, 1951
.
This decision is supported by our observation that species diversity in the genus
Eobroscus
is lower than expected: We could compare several specimens from
Vietnam
(coming from the type locality of
E. uenoi
Morita 1995
) with the
holotype
of
E. bhutanensis
Morvan, 1982
, and with additional specimens from
China
,
Myanmar
,
Nepal
and northeast
India
, and we could determine identity. Based on a careful examination of this material we can state that all differential characters of
E. uenoi
mentioned by
Morita (1995)
fall in the variability of the species
E. bhutanensis
: (i) body size
15.7–16.1 mm
(
15.9–16.3 mm
in
E. uenoi
); (ii) coloration of dorsal side of body brown to black with +
/
– prominent metallic lustre (see
Figure 2B
; body almost black in
E. uenoi
with greenish lustre on elytra); (iii) aedeagus relatively robust (see
Figure 5
C– F; identical in
E. uenoi
, see
Morita 1995: 9
); (iv) lateral and dorsal wing-like expansions of aedeagal median lobe markedly produced (see
Figure 5
C–F; identical in
E. uenoi
, see
Morita 1995: 9
). Therefore, we propose
E. uenoi
mentioned by
Morita (1995)
as a junior synonym of
E. bhutanensis
Morvan, 1982
, a macropterous species with a wide distribution along the Himalayan chain and in neighbouring mountainous areas of South
East Asia
(
Figure 7
).
Hence, the genus
Eobroscus
encompasses actually no more than three species. We believe that this is an additional argument against splitting the genus into two subgenera.
In addition, we have doubts about the status of
E. masumotoi
Morita, 1990
as a distinct species. Based on the comparison of two female specimens from the type locality with the
E. bhutanensis
material listed above we have to reject four of the six differential characters mentioned by
Morita (1990: 164)
because they fall within the variability of the species
E. bhutanensis
: (i) the colour of the body surface; (ii) the length of the temples in proportion to the length of the eyes; (iii) the shape of the pronotum; (iv) the shape of the elytra. We have to confirm the observation of
Morita (1990)
that specimens of the Taiwanese population (
E. masumotoi
) are somewhat smaller (
14.9 mm
;
Morita 1990: 160
:
14.5–15.2 mm
) than specimens from the continent (
E. bhutanensis
,
15.7–16.1 mm
). By comparing our preparations of
E. bhutanensis
aedeagi (e.g.
Figure 5
C–F) with the figuring of the
E. masumotoi
holotype
specimen (
Morita 1990: 163
) we also confirm that the median lobe of the latter is slightly shorter. In addition, lateral wing-like expansion on the right seems lesser developed in the
E. masumotoi
holotype
than in specimens of
E. bhutanensis
. However, apart from the
holotype
no additional male specimens of
E. masumotoi
have been described or recorded in the literature and so, the true variability of the external shape of the aedeagus remains unknown for us. For this reason the decision to confirm or to reject the species status of
E. masumotoi
has to wait until further material from
Taiwan
becomes available.