Anatheta Casey, 1910

Ashe, James S. & Gusarov, Vladimir I., 2003, Review of Anatheta Casey (Staphylinidae: Aleocharinae: Athetini), with Notes on Synonymy of Canastota Casey and Silusida Casey, The Coleopterists Bulletin 57 (1), pp. 27-36 : 28-32

Anatheta Casey, 1910

Casey 1910:112 (as a subgenus of Sableta Casey 1910 in his group Athetae of the tribe Myrmidoniini (sic!)); Fenyes 1920:221 (as a synonym of Atheta (Sableta) Thomson 1858 in the tribe Myrmedoniini ); Bernhauer & Scheerpeltz 1926:666 (as a synonym of Atheta (Sableta) Thomson 1858 , in subtribe Athetae of the tribe Myrmedoniini ); Seevers 1978:104 (as a genus in the tribe Athetini ); Ashe 2000:370 (as a genus in the Athetini )

Type Species. Sableta (Anatheta) planulicollis Casey 1910 , by original designation.

Diagnosis. Among North American aleocharines with 4-5-5 tarsal segmentation and narrowly separated or contiguous mesocoxae, specimens of Anatheta can be easily recognized by the combination of: rather flattened, parallel-sided body ( Fig. 1 ); brown coloration; densely reticulate head, pronotum and elytra, surfaces appearing dull; pronotum with microsetae directed posteriorly in the midline, and laterally in lateral areas (Type II, Höeg 1945); pronotal macrosetae inconspicuous, short; numerous spines on the anterior and middle tibiae ( Figs. 10, 11 ), posterior tibia without spines ( Fig. 12 ); short, very acutely pointed mesosternal process (extending not more than ½ length of mesocoxal cavities), very short metasternal process, and relatively long isthmus ( Fig. 9 ): spermatheca very small ( Figs. 17 , 20).

Description. Length of known species 2.5–3.5 mm. Known species with body color light to medium brown, most with darker head and abdominal segments. Body form ( Fig. 1 ) flattened, parallel-sided, abdomen slightly narrower than elytra at base, parallel-sided. Head, pronotum and elytra with strong, dense reticulate microscuplture, surface appearing dull; abdominal terga with less dense, transverse microscuplture, surface appearing glossy.

Head subquadrate, more or less rounded behind, eyes subequal to, or slightly shorter than, length of temples behind eyes in dorsal aspect, eyes not bulging or prominent; infraorbital carina complete but weak in most, fading just before contact with maxillary fossa in some; neck absent. Antenna short, article 4 subquadrate, articles 5–10 transverse, apical antennal article without coeloconic sensillae. Labrum ( Fig. 2 ) transverse and more or less truncate apically, apical margin not membranous medially, a-sensory setae short, setose. Adoral surface of labrum (epipharynx) as in Figure 3 . Mandibles ( Figs. 4, 5 ) asymmetrical, right mandible with a small medial tooth, medial tooth absent from left mandible; ventral molar area without patches of denticles ( Fig. 5 ); ‘‘velvety patch’’ of dorsal molar region ( Fig. 4 ) consisting of dense patch of minute spinules (visible only under magnifications greater than 4003 with compound optics). Maxillary palpi ( Fig. 6 ) 4-articled; article 1 short, about 1/3 as long as article 2; articles 2 about 4/5 length of 3; article 4 about 1/3 as long as article 3. Maxilla ( Fig. 6 ) with galea slightly longer than lacinia, sclerotized in basal 2/3, apical 1/3 membranous and covered with numerous short, closely arranged setae; apical third of lacinia with distinct row of closely spaced spines, middle third produced medially and covered with numerous spines and setae; basal third without spines or setae. Labium as in Figure 7 ; labial palpi 3- articled; ligula short, divided into 2 lobes in apical 1/3; 2 discal setae of prementum with bases moderately distant, separated by about width of their punctures; medial pseudopore field narrow, with 3–5 irregular pseudopores; lateral areas with pair of twin pores, a prominent spinose pore and 12–15 irregular pseudopores. Hypopharyngeal lobes as in Figure 8 . Mentum with anterior margin truncate, anterolateral angles not produced as prominent spinose processes.

Pronotum transverse, 1.2–1.3 times wider than long in known species; broadest slightly in front of middle, sides broadly rounded, dorsal surface rather flattened, broadly convex in cross section; anterior margin slightly arcuate, antero-lateral angles distinct, postero-lateral angles rounded; posterior margin rounded; uniformly covered with short microsetae, microsetae in midline directed posteriorly, microsetae in lateral areas directed laterally (Type II, Höeg 1945); macrosetae short, limited to one macroseta at each apico-lateral angles and one on each lateral margin slightly anterior to middle; hypomera inflexed, but fully visible in lateral aspect ( Casey (1910, p. 112) states that the hypomera are ‘‘... horizontal but warped...’’ so that only a small part of the hypomera near the coxae are visible; however, this is incorrect.). Postero-lateral angles of elytra slightly sinuate. Known species with hind wings present and fully developed. Meso—metasternum as in Figure 9 , mesosternal process short, narrow, acutely pointed, extended 1/2 length of mesocoxal cavities, apex distant from that of very short metasternal process; isthmus equal in length to that of mesosternal process; mesosternum and mesosternal process not carinate medially; known species with relative lengths of mesosternal process: isthmus: metasternal process in ratio of about 4:3:1 ( A. planulicollis ) to 3.4:3:1 ( A. surrufa ); mesocoxal cavities margined behind; mesocoxae narrowly separated. Front tibia ( Fig. 10 ) with numerous short strong spines on posterior and external surface and middle ( Fig. 11 ) tibia with numerous short spines on external surface; hind tibia ( Fig. 12 ) without spines on external surface. Tarsal segmentation 4,5,5; article 1 of hind tarsus about as long as article 2 ( Fig. 12 ). Two empodial setae present, setiform, short, shorter than ½ length of tarsal claws, one slightly longer than the other. Hind coxae without ventral plate that covers base of femur and trochanter.

Figs. 18-20. Anatheta surrufa (Casey) . 18) Aedaegus, lateral aspect; 19) aedeagus, dorsal aspect; 20) spermatheca.

Abdominal terga III–V with moderate transverse basal impressions. Tergum VII slightly longer than VI; terga VII and VIII of similar length. Puncturation of terga III–VI equally dense, puncturation of tergum VII only a little sparser. Anterior margin of abdominal tergum VII modified in conjunction with well-developed gland reservoir. Abdominal tergum X subquadrate, apical 1/3 divided into two lateral setose regions by medial lightly sclerotized area. Sternum VIII ( Fig. 14 ) of both sexes longer than tergum VIII ( Fig. 13 ), but much more so in males. Male sternum VIII without apical dorsal setae. Female sternum VIII with row of apical microsetae (as in other Athetini ).

Spermatheca extremely small ( Figs. 17 , 20).

Discussion. The type species of Sableta is S. (s. str.) infulata Casey 1910 by original designation. Casey did not specifically state in his description of Sableta that S. infulata was the type species of Sableta ; however, while designating the type species of Noverota Casey 1910 in the same paper, Casey stated (1910, p. 90): ‘‘The first species may be regarded as the type, as in all other cases where the type is not specifically named.’’ We accept the opinion of Blackwelder (1952) that this is valid original designation of the type species. Sableta (Anatheta) planulicollis (the type species of Anatheta ) is not congeneric with S. infulata . Thus Anatheta is validly recognized as a genus distinct from Sableta (as done by Seevers 1978 and Ashe 2001).

Seevers (1978, p. 104) retained the name Anatheta ‘‘...as an expediency’’, but believed that it is difficult to separate Anatheta from Canastota Casey (type species Sableta (Canastota) canadensis Casey 1910 ) which Casey also treated as a subgenus of Sableta . In spite of Seevers’ opinion, Anatheta and Canastota are not closely related. S. (Canastota) canadensis Casey 1910 (the type of Canastota ) is not an athetine; it is, instead, conspecific with Silusida marginella ( Casey 1893) , a homalotine in the subtribe Bolitocharina . Below we designate lectotypes that stabilize the application of these names.

Casey (1911) discussed the possibility of a subspecific relationship between two new species, Metaxya surrufa and Metaxya erudita ; he noted they are very similar and from the same locality. However, he rejected the subspecific ranking in favor of considering them separate species. In fact, our studies show that M. erudita is conspecific with Anatheta planulicollis , and M. surrufa is a separate species but clearly congeneric with A. planulicollis .

Both Casey (1910) and Seevers (1978) were correct in their opinion that Sableta (Anatheta) curata Casey 1910 is not congeneric with Anatheta planulicollis . In fact, S. (A.) curata is very similar to members of the genus Acrotona .

Anatheta is similar to Philhygra Mulsant et Rey 1873 in general body form and in having very small spermatheca. However, Anatheta can be easily distinguished by presence of strong spines on the anterior and middle tibia and in having pronotal pubescence of pronotum of Type II ( Höeg 1945). Anatheta shares with the Palaearctic genus Taxicera Mulsant et Rey 1873 presence of strong spines in the anterior and middle tibia, and pronotal pubescence pattern of Type II. However, Taxicera differs in having a glossy body with very sparse pubescence and normally developed spermatheca.

The two known species are very similar and can only be reliably distinguished by their distinctive aedeagi and the different sizes of their spermathecae. Though A. surrufa is slightly smaller (body length 2.5–3.0 mm in comparison to 2.9–3.5 mm for A. planulicollis ) and on average slightly darker (see description below), these features overlap in some specimens and cannot reliably be used for distinguishing between these. Characters they share are included in redescription of the genus above and are not repeated in species descriptions below.

Figures

Fig. 1. Anatheta planulicollis (Casey) habitus, length 5 3.2 mm.

Figs. 9–17. Anatheta planulicollis (Casey). 9) Meso-metasternum; 10) left anterior tibia and tarsus; 11) left middle tibia and tarsus; 12) left hind tibia and tarsus; 13) male tergum VIII; 14) male sternum VIII; 15) aedaegus, lateral aspect; 16) aedeagus, dorsal aspect; 17) spermatheca.

Figs. 2–8. Anatheta planulicollis (Casey). 2) Labrum, dorsal aspect; 3) labrum, adoral aspect (epipharynx); 4) left mandible, dorsal aspect; 5) left mandible, ventral aspect; 6) maxilla, ventral aspect; 7) labium, ventral aspect; 8) hypopharyngeal lobes, adoral aspect.