Idahotyphlus Gusarov

Gusarov, Vladimir I., 2003, Idahotyphlus alleni Gusarov, gen. n., sp. n., a new leptotyphline staphylinid beetle from Idaho (Coleoptera: Staphylinidae: Leptotyphlinae), Zootaxa 345, pp. 1-8 : 2-5

Idahotyphlus Gusarov , gen. n. ( Figs. 1–22 )

Diagnosis. Based on the presence of the procoxal fissure, the dilated second and third articles of the maxillary palpus and the absence of deep transverse basal furrows of abdominal sterna, Idahotyphlus is assigned to the tribe Neotyphlini Coiffait, 1963 . Idahotyphlus can be distinguished from the other genera of that tribe by the combination of the following characters: labrum with three small denticles at the anterior margin; each mandible with a single subapical tooth and smooth internal edge; prostheca present; last segment of the maxillary palpus long; completely separate gular sutures; frontal swelling above the antennal insertions interrupted in the middle; a long prosternal process; aedeagus, when retracted in the abdomen, with the basal orifice facing right, with the apical orifice shifted to the left side, and with an extremely long needle­shaped sclerite of the internal sac protruding out of the median lobe; and no parameres visible at 200x.

Idahotyphlus is similar to Cainotyphlus Coiffait, 1962 in having a narrow median lobe of the aedeagus with reduced parameres and a long and partially exposed sclerite of the internal sac. However, in Idahotyphlus the sclerite of the internal sac is needle­shaped and as long as the median lobe. As a result, in Idahotyphlus the aedeagus is half as long as the entire body when the sclerite is projected. In some of the examined male specimens the apical portion of the aedeagus was exposed. In addition, Idahotyphlus differs from Cainotyphlus in having a smooth inner edge of the mandibles (crenulate in Cainotyphlus ); three small denticles on the anterior margin of the labrum (two denticles in Cainotyphlus ) and a different distribution of macrosetae on the labrum ( Fig. 5 : this paper; Figs. 29, 34: Coiffait (1962)).

Description. Length 1.4–1.7 mm. Body brownish yellow, poorly pigmented, dorsal surface with isodiametric microsculpture.

Head slightly convex laterally ( Figs. 1–2 ). Labrum ( Fig. 5 ) with three small tubercles at anterior margin (in exactly dorsal view), with small medial tubercle (visible in oblique dorsal view: Fig. 1 ). Mandible with single subapical tooth and developed prostheca ( Figs. 6–7 ). Maxillary palpus with dilated articles 2 and 3, last article long and narrow ( Fig. 8 ).

Antenna with articles 3–10 transverse, with setae arranged in two belts, article 11 with evenly distributed setae, articles 9–11 with a few clavate setae in subapical portions ( Fig. 10 ). Gular sutures completely separate posterior to tentorial pits ( Fig. 2 ). Frontal swelling above antennal insertions interrupted medially ( Fig. 1 ).

Pronotum with two weak longitudinal impressions along midline. Procoxal fissure present as anterolateral notch in procoxal cavity and extends anteriorly as suture ( Figs. 3– 4 ). Prosternal process long ( Fig. 3 ). All tibiae with two rows of setae ( Figs. 11–14 ), the row on internal surface of protibia 0.6 times as long as tibial length. Tarsal formula 3­3­3 ( Figs. 11–14 ).

Abdominal sterna without transverse basal furrows.

Aedeagus long and narrow, without denticle on parameral surface ( Figs. 15–20 ), when retracted in abdomen, with basal orifice facing right. No visible parameres at 200x. Apical orifice of median lobe shifted to left side. Internal sac with long needle­shaped sclerite which is as long as median lobe; when retracted the sclerite exposed apically. Aedeagus with completely projected internal sclerite ( Figs. 15, 18, 20 ) 0.7–0.8 mm long, with retracted sclerite 0.45 mm long.

Type species. Idahotyphlus alleni Gusarov , sp. n.

Etymology. The name Idahotyphlus is derived from word Idaho (the type locality state) and the Greek adjective ó (blind). Gender: masculine.

Discussion. To recognize Idahotyphlus , the most recent key to Nearctic leptotyphline genera ( Newton et al. 2000: 323) is modified as follows:

6(3). Ridge on front of head between antennae obsolete medially ( Fig. 1 : this paper); mandible with a single large tooth on mesal edge, not serrate ( Figs. 6–7 : this paper); labrum with one pair of large setae near anterior edge and two pairs of large setae on disk ( Fig. 5 : this paper) ......................................................................................... 6a

– Ridge on front of head between antennae complete; mandible, in addition to large preapical tooth, with more basal second large tooth, or serrations, or both (see Coiffait (1962), Figs. 55, 35, 45–50); labrum with two pairs of large setae near anterior edge and one pair of large setae on disk (Figs. 29, 34) ........................................... 7

6a(6).Sclerite of internal sac shorter than median lobe, not needle­shaped (see Coiffait (1962), Fig. 42); apical orifice shifted to right side of median lobe (see Coiffait (1962), Fig. 42) ................................................................................... Homeotyphlus

– Sclerite of internal sac as long as median lobe, needle­shaped ( Figs. 15, 18, 20 : this paper); apical orifice shifted to left side of median lobe ( Fig. 20 : this paper)

................................................................................................................ Idahotyphlus

Figures

FIGURES 1 – 10. Details of Idahotyphlus alleni Gusarov, gen. n., sp. n. (male (3, 9) and female (1 – 2, 4 – 8, 10) paratypes from Beaver Creek Summit, Idaho). 1 — forebody, dorsal view; 2 — head, ventral view; 3 — prothorax, ventral view; 4 — prothorax, lateral view; 5 — labrum; 6 — right mandible, dorsal view; 7 — left mandible, dorsal view; 8 — right maxilla, ventral view; 9 — prementum, ventral view; 10 — right antenna. Scale bar 0.1 mm (5 – 10), 0.2 mm (1 – 4).

FIGURES 11 – 14. Legs of Idahotyphlus alleni Gusarov, gen. n., sp. n. (male (11, 13 – 14) and female (12) paratypes from Beaver Creek Summit, Idaho). 11 – 12 — left anterior leg; 13 — left middle leg; 14 — left posterior leg. Scale bar 0.1 mm.

FIGURES 15 – 22. Details of Idahotyphlus alleni Gusarov, gen. n., sp. n. (male (15 – 21) and female (22) paratypes from Beaver Creek Summit, Idaho). 15 — aedeagus with extended internal sclerite, parameral view; 16 — apex of the sclerite of internal sac, parameral view; 17 — apex of the median lobe, parameral view; 18, 20 — aedeagus with extended internal sclerite, lateral view; 19 — apex of the sclerite of internal sac, lateral view; 21 — male sternum 8; 22 — female abdominal segments 9 – 10, ventral view. Scale bar 0.1 mm (16 – 17, 19, 22), 0.2 mm (15, 18, 20 – 21).