A revision of the genus Seeversiella Ashe, 1986 (Coleoptera: Staphylinidae: Aleocharinae)
Author
Gusarov, Vladimir I.
text
Zootaxa
2003
142
1
102
journal article
51371
10.5281/zenodo.156420
76c096e3-d27c-4abc-a504-a62ae8c7ba92
11755326
156420
Seeversiella
Ashe, 1986
(
Figs. 1384
)
A new genus:
Seevers, 1978
: 46 (unnamed new genus appearing in a key).
Seeversiella
Ashe
: 1986: 501 (tribe
Athetini Casey, 1910
).
Seeversiella
: Ashe
in
Newton, Thayer, Ashe & Chandler, 2000
: (tribe
Athetini
, not assigned to subtribe).
FIGURES 15
. Mouthparts of
Seeversiella globicollis
(Bernhauer)
(Waterton Lakes National Park, Alberta). 1 – labrum; 2 – epipharynx; 3 – right maxilla, ventral view; 4 – left mandible, dorsal view; 5 – right mandible, dorsal view. Scale bar 0.1 mm.
Diagnosis.
Seeversiella
can be distinguished from other athetine genera by the combination of the following characters: body parallelsided or with broad ovate abdomen (
Figs. 1719
); antennal articles 810 transverse (
Fig. 9
); ligula divided into two separate lobes (
Fig. 6
); pronotum with microsetae directed posteriorly along the midline; in lateral portions of the disc microsetae directed towards the midline and/or obliquely posteriorly (
Figs. 1012
) (posteriorly in
S. geostiboides
); pronotal macrosetae short; pronotal hypomera fully visible in lateral view; medial macroseta of mesotibia inconspicuous, shorter than tibial width; tarsal formula 455; metatarsal segment 1 as long as segment 2; one empodial seta; in many species posterior angles of male tergum 3 projecting as spines (
Figs. 15
,
17
), long in large males, short or absent in small males (
Figs. 10
A10C in
Ashe (1986))
; in many species male tergum 7 with medial carina along midline (
Figs. 1718
) (absent in small males); copulatory piece of internal sac of aedeagus long and flagellumlike (
Figs. 29, 36
; CP).
FIGURES 69
. Mouthparts and antenna of
Seeversiella globicollis
(Bernhauer)
(67, 9, Waterton Lakes National Park, Alberta; 8, Anticosti, Quebec). 6 – prementum; 7 – hypopharynx; 8 – mentum; 9 – right antenna. Scale bar 0.1 mm (68), 0.2 mm (9).
Seeversiella
differs from
Geostiba
in having microsetae of lateral portions of pronotum directed towards the midline; posterior angles of male tergum 3 projecting as spines; and long flagellumlike copulatory piece of internal sac of aedeagus.
Seeversiella
differs from
Tropimenelytron
Pace,
1983
in having contiguous mesocoxae; ligula divided into two separate lobes; microsetae of lateral portions of pronotum directed towards the midline; posterior angles of male tergum 3 projecting as spines; and long flagellumlike copulatory piece of internal sac of aedeagus.
Seeversiella
differs from the small species of
Atheta
Thomson, 1858
with transverse antennal segments in having ligula divided into two separate lobes; microsetae of lateral portions of pronotum directed towards the midline; posterior angles of male tergum 3 projecting as spines; and long flagellumlike copulatory piece of internal sac of aedeagus.
Description.
Length
1.63.7 mm
, pronotal width
0.340.74 mm
. Body parallelsided or with broad ovate abdomen (
Figs. 1719
), dark brown to brownish yellow.
Head as wide as long; eyes small or large, temple length to eye length ratio 0.87.0; infraorbital carina incomplete. Antennal article 2 longer or as long as article 3, articles 45 slightly elongate, subquadrate or slightly transverse, 67 subquadrate or transverse, 810 transverse or strongly transverse (ratio 1.52.0), apical article without coeloconic sensilla. Labrum (
Fig. 1
) transverse, anterior margin slightly concave. Adoral surface of labrum (epipharynx) as in
Fig. 2
. Mandibles (
Figs. 45
) broad, right mandible with a small medial tooth; dorsal molar area with velvety patch consisting of very small denticles (not visible at 400x). Maxilla (
Fig. 3
) with galea extending beyond apex of lacinia; apical lobe of galea covered with numerous fine and short setae; apical fifth of lacinia with row of closely spaced spines, middle portion produced medially and covered with numerous setae. Labium as in
Figs. 68
; ligula divided into two lobes; medial area of prementum without pores but with 515 pseudopores, lateral areas with 3 (occasionally 4) pores and single spinose pore (
Fig. 6
). Hypopharyngeal lobes as in
Fig. 7
. Mentum (
Fig. 8
) with slightly protruding anterior angles and straight anterior margin.
Pronotum (
Figs. 1012
) slightly transverse, broadest near middle, sides slightly convex; anterior and posterior margins convex; surface covered with microsetae directed posteriorly in midline; in lateral areas of the disc microsetae directed towards midline and/or obliquely posteriorly (posteriorly in
S. geostiboides
); macrosetae short; hypomera fully visible in lateral view. Meso and metasternum as in
Fig. 12
, mesosternal process extending about ½ length of mesocoxal cavities, metasternal process short, mesosternum and mesosternal process not carinate medially; relative lengths of mesosternal process: isthmus: metasternal process in ratio of about 3:3:1; mesocoxal cavities margined posteriorly; mesocoxae contiguous. Medial microseta of mesotibia inconspicuous, shorter than tibial width. Tarsal segmentation 455, metatarsal segment 1 as long as segment 2. One empodial seta, slightly shorter than claws. Wings fully developed, partially reduced or reduced to short vestiges that are shorter than elytra. Posterior margin of elytra straight or slightly concave near posterolateral angle.
FIGURES 1016
. Details of
Seeversiella globicollis
(Bernhauer)
(10, Anticosti, Quebec; 13, Waterton Lakes National Park, Alberta),
S. scabricollis
Gusarov
,
sp. n.
(11, 15, paratype from Volcán Barva, Costa Rica) and
S. micralymma
Gusarov
,
sp. n.
(12, 14, 16, paratype from Cerro Buenavista, Costa Rica). 1012 – pronotum; 1314 – mesometathorax; 15 – male tergum 3 and paratergites; 16 – male tergum 3. Scale bar 0.4 mm (1011, 15), 0.3 mm (1213, 16), 0.2 mm (14).
Abdominal terga 35 with moderate basal impressions. Tergum 7 as long as tergum 6. Punctation on terga 67 sparser than on terga 35. Tergum 7 with wide white palisade fringe or without fringe (in wingless species).
In many species posterior angles of male tergum 3 projecting as spines (
Figs. 15
,
17
), long in large males, short or absent in small males (
Figs. 10
A10C in
Ashe (1986))
; in some species lateral portions of posterior margin of male tergum 3 extending as short and obtuse projections (
Figs. 16
,
1819
); in most species male tergum 7 with medial carina along midline (
Figs. 1718
) (absent in small males) or with medial subapical tubercle. Copulatory piece of internal sac of aedeagus long and flagellumlike (
Figs. 29, 36
; CP); medial lamellae narrow (
Figs. 2930
; 47; 258; ML). Internal sac with one pair of distal sclerites (not homologous to suspensoria) laterally of copulatory piece; the distal sclerites are hookshaped (
Figs. 2829, 31, 35
), dentiform (
Figs. 63, 65
) or reduced to elongate (
Figs. 199200, 203, 206
) or subquadrate (
Fig. 343
) plates which may have numerous spicules (
Figs. 99101
). Spermatheca short, S, L, J or Cshaped (
Figs. 32
,
53
,
62
,
104
,
149
,
205
).
FIGURES 1719
. Body outline of
Seeversiella globicollis
(Bernhauer)
(17, Volcán Tacana, Mexico),
S. micralymma
Gusarov
,
sp. n.
(18, paratype from Cerro de la Muerte, Costa Rica) and
S. flavida
Gusarov
,
sp. n.
(19, paratype from Cerro de la Muerte, Costa Rica). Scale bar 1 mm.
Type
species.
Seeversiella bispinosa
Ashe, 1986
, by original designation.
Discussion.
Although most species of
Seeversiella
described below can be recognized by comparing the external shape of the aedeagus, the details of the internal sac provide additional characters to distinguish the closely related species. Some characters of the internal sac, like long flagellumlike copulatory piece (
Figs. 29
; 172; 200, 203204; 301; CP) and narrow medial lamellae (
Figs. 2930
; 274275; 304305; ML), are consistent within the genus. The base of the copulatory piece and the medial lamellae are linked together by two connecting bands (
Figs. 243245
; CB). These bands are sclerotized areas of the internal sac wall. In everted internal sac the bands are situated on the parameral face of the sac (
Fig. 245
; CB). When the sac is retracted the bands are clearly visible laterally of the copulatory piece (
Fig. 243
; CB).
Other elements of the internal sac may differ significantly between species. One such element is a pair of distal (in everted sac) sclerites located laterally of the copulatory piece (
Figs. 2829
; DS). These sclerites are not attached to the copulatory piece and probably they are not homologous to suspensoria. In
S. globicollis
and
S. texana
the distal sclerites are hookshaped (
Figs. 31
; 51) and, when retracted, lie in the separate pockets of the internal sac. In many species the distal sclerites are reduced to elongate (
Figs. 199200, 203, 206
) or subquadrate (
Fig. 343
) plates which may have numerous spicules (
Figs. 99101
). The homology of these plates to the hookshaped sclerites of
S. globicollis
can be established by their similar position in the internal sac, laterally of the copulatory piece (
Figs. 2829
; 199200, 203204). Another detail of the internal sac which varies within the genus is the lateral diverticula which may be covered with numerous setae (
Figs. 29
; 169, 172 173; LD), have sclerotized denticles (
Fig. 200
) or possess long spiniform sclerites which may look like the medial lamellae but their location in the internal sac is different (
Figs. 301, 304
; 318; SLD). In retracted sac, the setae, the denticles or the sclerites of the lateral diverticula are usually well visible in cleared preparations (
Figs. 173
; 299, 303; 316; 327).
In
Seeversiella
, as in many other aleocharine genera (e.g.,
Geostiba
,
Tropimenelytron
) the male secondary sexual characters are subject to intraspecific variation. Larger males have longer spines on male tergum 3 (up to 3 times as long as tergum medial length) and longer carina on tergum 7. In smaller males the spines are very short or absent altogether. Therefore the male secondary characters cannot be reliably used to distinguish the species of
Seeversiella
.
My examination of available specimens of
Seeversiella
suggests that some species differ from each other in the length of elytra and wings, and in the eye size. On several occasions these characters are used below in the key to species. However, these characters should be used with caution because some species are polymorphic. Ultimately the details of male genitalia are the most reliable characters to recognize the species of
Seeversiella
.