Custotychus spinosus 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

6. Custotychus spinosus Chandler and Geromini , new species

( Figs. 7 , 21a–b , 30 , 34 )

Specimens Examined. n = 2 1. H o l o t y p e male: // USA.AL. Blount Co. Nr. Highland Lake 33.88253°N 86.42185°W 285m. 28 May 2003. T. King Berlese / LSAM 0293949 / [red label] HOLOTYPE Custotychus spinosus Chandler & Geromini // ( FMNH) . Paratypes: Alabama: Blount Co.: Nr. Highland Lake , 285m, V-28-2003, T. King, berlese (1M, DSCC; 8M, LSAM) . Colbert Co.: Cane Creek Canyon N[ature] P[reserve], III-24- 2014, J.A. MacGown & J.G. Lewis, berlese litter from upland hardwood forest (1M 2F, MEMC) . Jackson Co.: 10 mi. N Scottsboro , V-16-1972, S. & J. Peck (1M, CNCI) . Walker Co.: Jasper, Devil’ s Ladder , VI-4-1984, T. King, florest floor debris (1M, FMNH) . Arkansas: Garland Co.: Jessieville , XI-26-2011, B. Baldwin, Berlese funnel leaf litter (1M, BBC) . Georgia: Clarke Co.: 5 mi. W Athens , II-8/21-1978 (1M, DSCC) , III-15/22- 1978 (1M, UGAC), XII-1/7-1977 (1M, UGAC), XII-8/16-1977 (1M, UGAC), C.L. Smith, pitfall trap. Kentucky: Edmonson Co.: Mammoth Cave National Park , Bruce Hollow, VIII-24/27- 1967, S. Peck & A. Fiske, berlese, log stump litter (1M, FMNH) .

Description. Body: Brown; 1.56–1.62 mm long. Male: Eyes with about 35 facets; metasternal tubercle ( Figs. 21a, b ) at posterior margin of metasternum; in lateral view, curving anteriorly, apex narrowly rounded, posterior face flat; in posterior view, lateral margins to apex slightly broadening, apex rounded; tubercle height 0.069 mm, maximum apical width 0.032 mm, minimum stem width 0.026 mm [tubercle measurements based on specimen from near Highland Lake, AL; LSAM]. Mesotibiae with large, slightly curved spine at middle on posteromesal margin ( Fig. 30 ), probably modified preapical spur, otherwise preapical spur lacking, apical spur short, bluntly pointed. Ventrite 2 broadly rounded at middle, ventrite 6 with small, faint, circular impression at middle. Aedeagus ( Fig. 7 ) 0.32 long mm; in dorsal view, median lobe elongate, narrow, lateral margins slightly concave throughout length, lateral arms of dorsal plate elongate but short, extending to point just beyond middle of median lobe, appearing shortly bifurcate at apex; in lateral view, median lobe pointed at apex, slightly swollen in apical half; lateral arms of dorsal plate with spur curved strongly ventrally, second spur curved weakly dorsally; parameres swollen in apical half, extending to point even with apex of median lobe, membranous areas small. Female: Unknown.

Collection Data Synopsis. Individuals were collected from February to June, and in August and December. They were collected by processing forest floor debris/litter and stump litter with Berlese funnels, and several were taken by pitfall traps. Specimens are present in the following collections: BBC, CNCI, DSCC, FMNH, MEMC, and UGAC.

Distribution. This species occurs in the southeastern states from Georgia to Arkansas ( Fig. 34 ). Specimens were examined from the following states: AL, AR, GA, and KY.

Etymology. The name for this species was suggested by the prominent spine of the mesotibiae.

Comments. Custotychus spinosus is generally similar to C. rothorum by form and placement of the metasternal tubercle, and by the general form of the genitalia. The presence of a median spine on the mesotibiae leads to rapid recognition of this species, and the median lobe has the lateral margins gently concave in dorsal view, while C. rothorum lacks the median mesotibial spine and the lateral margins of the median lobe are straight.

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.

Figs. 28–32. Custotychus species. 28) C. pocahontas, scanning electron micrographs of right lateral (a) and posterior (b) views of metasternal tubercle. Grid for measurements of 20 or 50m at bottom of micrographs; 29) C. carloritaorum, mesotibial spurs; 30) C. spinosus, mesotibial spurs; 31) C. watrousi, abdominal ventrites, ventrolateral view; 32) C. daggyi, right maxillary palpus, ventral view. Scale bar = 0.1 mm.

Figs. 34–36. Distribution of Custotychus species. 34) Distribution of species in the spinosus and verticalis species-groups: C. rothorum and C. spinosus, and C. cavei, C. verticalis, and C. watrousi; 35) Distribution of C. minor; 36) Distribution of other species in the minor species-group: C. carloritaorum, C. leei, C. natchez, and C. pocahontas.