Seeversiella Ashe 1986
Creators: name: Gusarov, Vladimir I.
Publisher: name: Zenodo
Year: 2003
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Staphylinidae
Seeversiella

description: 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).
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).
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.
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).
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.
description: Published as part of Gusarov, Vladimir I., 2003, A revision of the genus Seeversiella Ashe, 1986 (Coleoptera: Staphylinidae: Aleocharinae), pp. 1-102 in Zootaxa 142 on pages 3-9, DOI: 10.5281/zenodo.156420