Polycentropus carlsoni Morse, 1971

Orfinger, Alexander Benjamin, 2023, Taxonomic revision of the Polycentropus confusus species group (Trichoptera: Polycentropodidae), Journal of Natural History 57 (41 - 44), pp. 1825-1916 : 1841-1845

Polycentropus carlsoni Morse

( Figures 9–10 , 39 )

Polycentropus carlsoni Morse, 1971: 78 , fig. 3, J; type locality ′ Wildcat Creek , Clemson, S .C̍. (INHS).

Polycentropus carlsoni Armitage and Hamilton, 1990 : figs. A–D, J.

Polycentropus carlsoni Hoffman and Morse, 1990: 277–278 , figs. 5–9, ♀.

Diagnosis. Males of P. carlsoni are most similar to those of P. aileenae , P. blicklei , P. carolinensis and P. maculatus . From males of these species, males of P. carlsoni are identified by the shorter, stockier and deflexed basodorsal process of each inferior appendages, the slightly ventrally recurved apex of the ventral portions of each inferior appendages, and the shape of the body of each pre-anal appendage which in P. carlsoni is round and lacking any posteroventral process.

Females of P. carlsoni are most similar to those of P. aileenae , P. blicklei and P. maculatus . Unlike the blade-like internal parts of gonopods VIII of P. aileenae , those of P. carlsoni are subrectangular. From P. maculatus , females of P. carlsoni are distinguished by the kukri blade-like shape of the ventral plates in ventral view that terminate beyond the internal parts of gonopods VIII, vs the subtriangular ventral plates that terminate anterior to the internal parts of gonopods VIII.

Adult description

General. Length. of male 5.2–6.9 mm (mean = 6.1 mm; n = 5). Length of female 6.1– 8.1 mm (mean = 6.9 mm; n = 5).

Male genitalia ( Figure 9A–E ). Abdominal segment VIII annular. Terga IX and X fused, membranous, extended caudad over bases of intermediate appendages. Sternum IX subovoid in lateral view. Intermediate appendages originating beneath terga IX+X and extending beyond them, curved slightly ventrad, their apices each bearing 4 small setae; in dorsal view apices proximate, subparallel. Bodies of pre-anal appendages each round, lacking posteroventral process; dorsal process long, curved ventrad, extending to apex of ventral portion of inferior appendage, acute apically; in dorsal view slender, elongate, subparallel. Inferior appendages in lateral view each with capitate basodorsal process deflexed with short neck and stocky subtriangular head round dorsally and projecting ventrad with its pointed apex occasionally visible above main body of appendage, occasionally hidden behind main body of appendage, main body of appendage tapering evenly along length, terminating in round, slightly dorsally recurved apex, terminating at approximately apex of dorsal process of pre-anal appendage; in ventral view tapering gradually along length, round apices inflected mesally, basodorsal process partially hidden by main body of inferior appendage, with only mesal margins exposed, in cleared specimen broad, with medial pointed projection; in caudal view oblong, with medial projection round. Phallus a fully sclerotised tube, in lateral view with large base, curved slightly ventrad slightly beyond mid-length, apical section subrectangular, internal spinules absent, internal phallic sclerite short, oriented posteroventrally, with acute anterior broadening to a subrectangular posterior apex.

Female genitalia ( Figure 10A–B ). Venter VIII in ventral view with ventral plates convergent, narrow, blade-like as a kukri sword, tapering apically, covered with setae; in lateral view each terminating in round posterior apex; posterior apex of external parts of gonopods VIII in ventral view with posterior margin mesally produced and round; in lateral view not extending beyond ventral plates in round process; internal parts of gonopods VIII in ventral view visible through venter VIII even in uncleared specimen, appearing longitudinally wrinkled, darker than surrounding tissue, subparallel, subrectangular, with apices distinctly anterior of apices of ventral plates; in ventral view anterior part of genital chamber sclerotised, subovate; processus spermathecae ovoid with central elevation bearing opening of ductus spermathecae.

Larva. Described by Orfinger et al. (2023).

Pupa. Unknown.

Notes. Moulton ̍s 2007 record of P . carlsoni from Tennessee is erroneous and was based on individuals (1 male, 1 female) of P . aileenae. In addition, although the holotype was initially deposited at the University of Georgia Collection of Arthropods , it was transferred to the Illinois Natural History Survey where it is currently housed.

Biology. This species is found at first- or second-order cool streams with rocky substrates. Adults of P. carlsoni have been collected from April to November while the only known, late-instar larva was collected in October. As noted by others (e.g. Moulton 2007), collections of this apparently uncommon species generally comprise fewer than five individuals. Unlike most Polycentropus species, adults of P. carlsoni have been collected most frequently using malaise traps or modified emergence traps, while only occasionally being taken in UV light traps. This suggests that perhaps this species flies earlier in the evening than other species or during the day under shaded riparian habitats with dense canopies.

Distribution ( Figure 39 ). USA: Alabama, Maryland, North Carolina , Pennsylvania, South Carolina , Virginia.

Given the known distribution of P. carlsoni , it would be unsurprising if it were eventually reported from northern Georgia, southern or eastern Tennessee, southern or eastern Kentucky, or West Virginia.

Material examined. Holotype: USA. South Carolina : Pickens County, Wildcat Creek, [N34°45 ʹ 34.20″, W82°51 ʹ 03.24″], P. Carlson coll., 23-iv-1968, 1 male (left inferior appendage broken; INHS Trichoptera 24,565). Paratype: USA. South Carolina : Pickens County, Wildcat Creek , [N34°45 ʹ 34.20″, W82°51 ʹ 03.24″], P . Carlson coll ., 23-iv-1968, 1 male ( INHS Trichoptera 24,564) .

Non-type material. USA. Pennsylvania: Philadelphia County, Tributary of Wissahickon Creek , at seep crossing trail, [N40°02 ʹ 38.04″, W75°12 ʹ 55.80″], N . Macelko coll ., 24-X-2021, 1 larva ( FAMU) . South Carolina : Pickens County, Clemson, Wildcat Creek, P . Carlson coll ., 12-v-1958, 1 female ( CUAC0000107319 ) . 1iv-1968, 1 female ( CUAC0000107323 ) . 20-iv -1968, 1 male ( CUAC0000107317 ) . 20-iv-1969, 1 male ( CUAC0000107316 ) . 24-iv-1968, 1 female ( CUAC0000107320 ) . Issaqueena Forest , N . Fork of Creek at Holly Springs Picnic Area , Malaise trap, 730 masl, K .M . Hoffman coll ., 12–20-vi-1988, 3 males ( CUAC0000107315 ) . 1 female ( CUAC0000107321 ) . 1 female ( CUAC0000107322 ) . Wildcat Creek , 770 masl, 27-vi-4-vii-1988, 1 female ( CUAC0000107318 ) . Virginia: Fairfax County, Gulch Stream, O .S. Flint coll ., vi-2008, 13 males, 27 females ( CUAC000107325 ) .

Figures

Figure 9. Polycentropus carlsoni Morse, 1971, male genitalia (holotype). A. left lateral (with phallus removed); B. dorsal; C. segment IX and inferior appendages, ventral; D. phallus, left lateral; E. dorsobasal process of right inferior appendage, caudal.

Figure 10. Polycentropus carlsoni Morse, 1971, female genitalia. A. left lateral; B. ventral.

Figure 39. Known Canadian province and US state distribution of Polycentropus carlsoni Morse, 1971, as indicated by grey shading.