Taxonomic notes on the Cephenniini (Coleoptera, Scydmaenidae): Status of Coatesia Lea, Cephennomicrus Reitter, and Neseuthia Scott
Author
Jałoszyński, Paweł
text
Zootaxa
2008
1696
25
36
journal article
10.5281/zenodo.274088
0488fc0c-9dd6-4030-87d7-9212ab8c7916
1175-5326
274088
Cephennomicrus typicus
(Scott)
,
comb. n.
Neseuthia typica
Scott, 1922
: 203
.
Type
material.
Lectotype
(designated here;
Figs. 5, 9
):
SEYCHELLES
:
Mahé
:
male, mounted on card bearing male symbol and number "117" handwritten in black, "
Mahe
, '08-9
Seychelles
Exp." (typed), "Percy Sladen Trust Exped. Brit.Mus. 1926―246." (typed), "
Type
" (circular, white with red margin, typed), "
Neseuthia typica
TYPE
. H.Scott [handwritten in black]
TYPE
[printed, highlighted in blue]", "
Figured specimen
" (red, printed), "
typicus Scott
[handwritten in black] Cl. Besuchet dét. [printed] X [handwritten in black] 195 [printed] 7 [handwritten in black]", "
NESEUTHIA typica
Scott
,
LECTOTYPE
; P. JAŁOSZYŃSKI, 2007" (printed), "
CEPHENNOMICRUS typicus
(Scott)
, det. P. JAŁOSZYŃSKI, 2007" (printed) (
BMNH
).
Paralectotypes
(
2 males
,
1 female
):
SEYCHELLES
:
Mahé
:
1 female
, mounted on card bearing female symbol and number "104", labels as in
lectotype
but lacking the red label "Figured specimen";
1 male
mounted on different (newer?) card than previous specimens, "
Paratype
" (circular, white with yellow margin, typed), "Percy Sladen Trust Exped. Brit. Mus. 1926-246" (typed), "
Neseuthia typica H. Scott
,
Paratype
" (printed), "
Mahe
, 1908-9.
Seychelles
Exp." (printed), and similar Besuchet's label as that shown in
Fig. 9
and found in all specimens;
1 male
mounted on the same
type
of card as the previous specimen, "
Paratype
" (circular, white with yellow margin, typed), "Ma(y?)e,
1908-09
,
Seychelles
Exp." (handwritten in black, in easily recognizable Besuchet's hand). All
paralectotypes
with additional labels "
NESEUTHIA typica
Scott
,
PARALECTOTYPE
; P. JAŁOSZYŃSKI, 2007" (printed), "
CEPHENNOMICRUS typicus
(Scott)
, det. P. JAŁOSZYŃSKI, 2007" (printed) (all specimens in
BMNH
).
FIGURES 4–9.
Type specimens of
Cephennomicrus perpunctillum
Reitter
and
Neseuthia typica
Scott.
4, Holotype male of
Cephennomicrus perpunctillum
(0.80 mm). 5, Lectotype male of
Neseuthia typica
(0.97 mm). 6, Aedeagus of the holotype of
Cephennomicrus perpunctillum
in dorsal view (0.17 mm). 7, Aedeagus of the paralectotype of
Neseuthia typica
in dorsal view (0.15 mm). 8. Set of original labels on the holotype of
Cephennomicrus perpunctillum
. 9, Set of original labels on the holotype of
Neseuthia typica
.
Remarks.
Besides the characters given in the diagnosis, all species of
Cephennomicrus
are extremely small, typically much smaller than
1 mm
in length. Very small species can also be found in the Palearctic genera
Nanophthalmus
and
Cephennium
, but the body as small as 0.6 mm, not uncommon in
Cephennomicrus
, makes this genus exceptional within the tribe. The body shape found in this genus is typical for the Cephenniini, with subquadrate pronotum and stout, short elytra, but the constriction between the pronotum and elytra is usually more distinct than in other genera. The antennae show some degree of variability, and since two relatively distinct variants can be found, in future they may be used for defining species groups or subgenera. Antennae in
C. perpunctillum
, the
type
species of
Cephennomicrus
, and in most of other described species, have two terminal antennomeres enlarged, and at first sight the antennal club appears two-segmented. However, closer examination usually reveals that antennomere IX, though clearly smaller than abruptly enlarged X and XI, is still much larger than VII, and can be regarded as belonging to the club. The other variant can be seen in several species, which have more slender antennal club, with antennomeres X and XI enlarged to a lesser extent than those in
C. perpunctillum
. In such cases (like in
C. nomurai
(Jałoszyński & Hoshina, 2003))
the club is very indistinctly separated from the funicle, but it still can be regarded as composed of 3 antennomeres. It can be concluded that
Cephennomicrus
has 3-segmented antennal club, and the extreme variants taken alone do not represent a diagnostic character to define separate taxa at the rank of subgenus or genus. However, the slender variant may co-occur with the longitudinal median groove on the pronotum found in some described and undescribed species from
Japan
and
Taiwan
; this combination, when confirmed, may serve as a potential subgeneric diagnostic feature.
The eyes in all species of
Cephennomicrus
known to the author are very large, strongly protruding laterally from the silhouette of the head, and usually coarsely faceted. This is an interesting character, as miniaturization in the Cephenniini often affects the eyes, which in such cases are usually very small or even entirely missing in minute subterraneous, lightly pigmented species of
Nanophthalmus
,
Cephennium
or
Etelea
. Oriental species of
Cephennomicrus
are rarely collected by methods based on sifting, but more frequently by flight intercept traps. The large eyes composed of a large number of ommatidia may therefore be important for flight-related activities.
A high degree of variability can be found in the shapes and structures of the aedeagus among the known species of
Cephennomicrus
; the
type
species of the genus and that of
Neseuthia
can be examples of such a difference (
Figs. 6, 7
). Again, a more comprehensive study is necessary to subdivide
Cephennomicrus
using structures of the aedeagus.