Custotychus chickasaw Chandler and Geromini, 1962

Chandler, Donald S. & Geromini, Sarah D., 1962, A Revision of the Eastern Nearctic GenusCustotychusPark and Wagner, 1962 (Coleoptera: Staphylinidae: Pselaphinae), The Coleopterists Bulletin 1962 (2), pp. 217-242 : 217-242

1. Custotychus chickasaw Chandler and Geromini , new species ( Figs. 2 , 16a–b , 33 )

Specimens Examined. n = 1 6. H o l o t y p e male: // USA, AR, Stone Co. S of Gunner Pool Campground / Berleseate 24 May 1988 / CE Carlton / LSAM 0293838 / [red label] HOLOTYPE Custotychus chickasaw Chandler & Geromini // ( FMNH) . Paratypes: Arkansas: Franklin Co.: 5.5 mi. N Cass at Cherry Bend , X-3-1974, A. Newton, hardwood berlese (2M 4F, LSAM) . Shores Lake at bridge crossing, L.E. Watrous, leaf litter, IX-22-2014 (1M 1F, UNHC) , IX-30- 2014 (1F, UNHC) . Johnson Co. : Haw Creek Falls Rec[reation] Area , III-22-2014, L.E. Watrous, leaf litter (1M, UNHC) . Newton Co.: 5.1 mi. S Mount Judes on Hwy. 123, III-25-1977, R. Chenowith, berlese hardwood pine (1M, LSAM) . Lost Valley, near Ponca , 1000′, X-23/24-1974, A. Newton, litter, mixed hardwood forest (1F, LSAM) . Stone Co.: S of Gunner Pool Campground , V-24-1988, C.E. Carlton, berlesate (1M, DSCC; 2M, LSAM) .

Description. Body: Light brown; 1.62–1.76 mm long. Male: Eyes with about 11 facets. Metasternal tubercle ( Fig. 16a–b ) slightly posterior to middle; in lateral view, erect, apex acutely pointed; in posterior view, broadly T-shaped, apex over twice width of narrowest point of stem, apex flat, posterior face flat, stem width less than half of apex width, height 0.054 mm, maximum apical width 0.104 mm, minimum stem width 0.041 mm (tubercle measurements based on specimen from south of Gunner Pool Campground, AR; LSAM). Mesotibiae with acute preapical spur, apical spur bifurcate, area of spurs slightly notched, with row of modified setae around perimeter of notch. Abdomen with ventrite 2 flattened in middle third; ventrite 6 with deep ovoid impression through length, anterior and lateral margins carinate. Aedeagus: ( Fig. 2 ) 0.42 mm long; in dorsal view, median lobe with parallel margins to truncate apex, in lateral view thick, slightly curved to bluntly rounded apex; dorsal plate with broadly V-shaped base, slightly angulate at lateral margins, apices of lateral arms membranous and with numerous striations in membranous portion of apical half, median portion of dorsal plate with lobe that is densely striate in membranous apical portion; in lateral view, basal bulb with prominent anteroapical projection; lateral arms of dorsal place with large ventral tooth at midpoint, apical portion transitioning to membranous striate area; parameres with margins gradually convergent to rounded apices. Female: Eyes with about 6 facets; lacking mesotibial spurs.

Collection Data Synopsis. Specimens were collected from September to November and in March and May. All were berlesed from hardwood leaf litters. Specimens in collections of DSCC, FMNH, UNHC, and LSAM.

Distribution. Only known from the Boston Mountains portion of the Ozark Mountains in Arkansas ( Fig. 33 ).

Etymology. This species is named for one of the indigenous tribes of the southeastern United States.

Comments. This is the only member of the daggyi species-group that has ventrite 2 impressed at the middle and a deep, marginally carinate impression on ventrite 6. It is also the only member of this species-group known from west of the Mississippi River. The relatively short median lobe is shared only with C. lobatus , and it shares the very broad apex of the metasternal tubercle with C. lobatus and C. turnbowi .

Figures

Figs. 1–7. Custotychus species. 1) C. natchez, dorsal habitus; 2–7) Aedeagus, dorsal and left lateral views:

Figs. 16–27. Custotychus species, scanning electron micrographs right lateral (a) and posterior (b) views of metasternal tubercle. 16) C. chickasaw; 17) C. daggyi; 18) C. lobatus; 19) C. turnbowi; 20) C. rothorum; 21) C. spinosus; 22) C. verticalis; 23) C. watrousi; 24) C. carloritaorum; 25) C. leei; 26) C. minor; 27) C. natchez. Grid for measurements of 20 or 50m at bottom of micrographs.

Fig. 33. Distribution of Custotychus species in the daggyi species-group: C. chickasaw, C. daggyi, C. lobatus, and C. turnbowi.