Polycentropus pentus Ross, 1941

Orfinger, Alexander Benjamin, 2023, Taxonomic revision of the Polycentropus confusus species group (Trichoptera: Polycentropodidae), Journal of Natural History 57 (41 - 44), pp. 1825-1916 : 1881-1885

Polycentropus pentus Ross

( Figures 28–29 , 50 )

Polycentropus pentus Ross, 1941: 71–72 , fig. 45, ♀; figs. 49–51, J; type locality ′ Thunder Bay , Ontario ̍ ( INHS) .

Polycentropus pentus Ross, 1944: 65 , fig. 242, J; fig. 269, ♀.

Polycentropus pentus Nimmo, 1986: 198 , figs. 160–164, J; figs. 165–166, ♀.

Polycentropus pentus Armitage and Hamilton, 1990 : figs. A–D, J; figs. E–F, ♀.

Polycentropus pentus Houghton, 2012 : fig. 277, J.

Diagnosis. Males of P. pentus are most similar to those of P. confusus in general appearance and those species that possess a round ventral swelling of the phallus, namely P. dinkinsorum , P. floridensis and P. vernus . From males of all of these species, those of P. pentus are distinguished by the mesocaudal processes of each body of the inferior appendages. From males of P. confusus , those of P. pentus are further distinguished by the presence of a basoventral swelling of the phallus and by the lack of microspinules on the apex of the phallus. From males of P. dinkinsorum , P. floridensis and P. vernus , those of P. pentus are also distinguished by the distinct shape of the basodorsal process of the inferior appendage.

Females of P. pentus show similarities to females of many species of the P. confusus species group and are identifiable by the unique shape of the wrinkled internal parts of gonopods VIII and by the sinuous dorsal margin of the posterior apex of external parts of gonopods VIII as seen in lateral aspect.

Adult description

General. Length. of male 8.0–10.0 mm (mean = 9.1 mm; n = 5). Length of female 8.5– 9.2 mm (mean = 8.9 mm; n = 5).

Male genitalia ( Figure 28A–E ). Abdominal segment VIII annular. Terga IX and X fused, membranous, extended caudad over bases of intermediate appendages. Sternum IX subovoid in lateral view, posterior margin slightly sinuous with ventral lip. Intermediate appendages originating beneath terga IX+X and extending beyond them, curved ventrad apically, their apices each bearing 4 small setae; in dorsal view apices proximate, subparallel, together appearing bifid. Bodies of pre-anal appendages each with apically round, subtriangular mesocaudal process bordered dorsally and ventrally by emarginations, posteroventral process shallow, round; dorsal process long, curved ventrad, extending to apex of basodorsal process of corresponding inferior appendage,acute apically,bearing at least one seta apicoventrally; in dorsal view slender, elongate, subparallel, slightly convergent apically. Inferior appendages in lateral view each with elongate basodorsal process erect with short neck and long digitiform head round dorsally, apex curved caudad, with sharp mesoventral point visible above main body of appendage, main body of appendage with dorsal and ventral margins concave for 1/5 length, tapering evenly beyond 1/5 length to round upturned apex terminating anterad of intermediate appendages; in ventral view subparallel, inner margin curved laterad basally for 1/3 length, curved mesad along middle 1/3 length, reaching widest point about mid-length, curving laterad for final 1/3 length, distally tapering to round apex, lateral margin and distal apex of basodorsal process exposed beyond lateral margins of main body of inferior appendage, apex of medial projection extending beyond medial margin of main body of inferior appendage, in cleared specimen elongate, with medial projection round; in caudal view subtriangular, with wide base and broad posteromesal projection round. Phallus a fully sclerotised tube, in lateral view with larger base bearing basoventral swelling, curved about 30° ventrad slightly beyond mid-length, apical section round with small ventral bump, internal spinules absent, internal phallic sclerite long, horizontal, with broad irregular basal apex deeply emarginate and slender distal apex subrectangular.

Female genitalia ( Figure 29A–B ). Venter VIII in ventral view with ventral plates convergent, semi-elliptical, 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 subtriangular and round mesally; in lateral view subtriangular, extending beyond ventral plates, dorsal margin sinuous; internal parts of gonopods VIII in ventral view visible through venter VIII even in uncleared specimen, appearing longitudinally wrinkled, darker than surrounding tissue, basally divergent, tapering to triangular base at sclerotised external part of gonopods VIII at basal third of ventral plates. distally subparallel, subrectangular, with mesocaudal corner slightly anterior of apices of ventral plates; in ventral view anterior part of genital chamber apparently absent; processus spermathecae semi-circular with distomesal elevation bearing opening of ductus spermathecae.

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

Pupa. Unknown.

Biology. Adults of this species have been collected from May to September using UV light traps and Malaise traps. Late-instar larvae have been collected from fast-flowing, cool streams with rocky and woody substrates from April to July. Unlike most wide-ranging species, P. pentus appears to be absent from the Coastal Plain physiographic region.

Distribution ( Figure 50 ). Canada: Manitoba, Newfoundland and Labrador, Nova Scotia, Ontario, Quebec; USA: Alabama, Connecticut, Illinois, Kentucky, Maine, Michigan, Minnesota, New Hampshire, New Jersey, New York, Ohio, Pennsylvania, Tennessee, Vermont, Virginia, West Virginia, Wisconsin, Wyoming.

This species has a wide distribution. Areas for which it is not known but where it has been taken from surrounding states or provinces are Indiana, Maryland, Delaware, Rhode Island, Massachusetts, and New Brunswick. Whereas all remaining members of the P. confusus species group are restricted to the eastern Nearctic Region, five specimens (three males, two females) of P. pentus were collected in Crook County, Wyoming, suggesting that a disjunct population exists. This could suggest that the species was previously much more widespread, and that the Wyoming specimens represent a relict population. Alternatively, and perhaps less likely, the Wyoming records could be the result of an introduced population.

Material examined. Holotype: Canada. Ontario: Thunder Bay , H.S. Parish coll., 1-vii- 1937, 1 male ( INHS Insect Collection 38,173) . Paratypes: Canada. Ontario: Algonquin Provincial Park, Costello Lake , Ontario Fisheries Research Laboratory , W.M. Sprules coll., 2-vi-1939, 4 males ( INHS Trichoptera 24,580), 1 female ( INHS Insect Collection 37,256) . 3-vi-1939, 2 males ( INHS Insect Collection 37,254) . 4-vi-1939, 4 females ( INHS Trichoptera 24,582) . 6-vi-1939, 4 females ( INHS Trichoptera 24,583) . Non-type material: Canada. New Brunswick: Moose Bog , [N47°15 ʹ 57.60″, W66°02 ʹ 27.60″], CC, AM, KB and MP coll., 2vi-2008, 1 male (08NBEPT-1300) . Newfoundland and Labrador: Gros Morne National Park, James Callaghan Trail (aka Gros Morne Trail ), Malaise trap, 39 masl, [N49°34 ʹ 06.96″, W57° 49 ʹ 48.72″], Anderson coll., 16-vii-2013, 1 male ( BIOUG10090 - F 07) . Tablelands Trail , 175 masl, [N49°28 ʹ 37.20″, W57°58 ʹ 12.00″], BIObus 2013 coll., 20-vii-2013, 1 male ( BIOUG14743 - A 01) . 1 male ( BIOUG15057 - D 03) . Nova Scotia: Kejimkujik National Park, Eel Weir Road , 96 masl, [N44°20 ʹ 53.52″, W65°11 ʹ 20.40″], BIObus2013 coll., 22-vi-2013, 1 female ( BIOUG16546 - G 04) . Jeremy`s Bay Campground , near Amphitheatre off of Campfire Circle , 116 masl, [N44°24 ʹ 23.76″, W65°14 ʹ 43.80″], D. Crossland and K. Rowter coll., 11-vii -2013, 1 female ( BIOUG11447 - F 01) . Ontario: Algonquin Provincial Park, small stream 2.5 km after North River Canoe Launch, 462 masl, [N46°04 ʹ 51.60″, W78°26 ʹ 19.68″], C. Freutel and G. Martin coll., 12-vii-2011, 1 larva ( BIOUG00331 - B 10) . 1 larva ( BIOUG00331 - C 05) . 1 larva ( BIOUG01723 - C 03) . 1 larva ( BIOUG01723 - D 05) . Bruce Peninsula National Park, Cyprus Lake Gate House, UV light sheet, [45°13 ʹ 48″, W81°31 ʹ 48″], BIObus 2008 coll., 14-vi -2008, 1 female (08ONCAD-0079) . gatehouse light, 12-vi-2008, 1 female (08ONCAD-0066) . Nipigon River , D.A. Etnier coll., 2-vii-2004, 2 males, 3 females ( ECC 3.432 ) . Quebec: Gatineau Park, near Hull, Fortune Creek at Ridge Road , W.E. Ricker coll., 20-vi-1965, 1 female ( INHS Trichoptera 54,357) . USA. Kentucky: Bell County, Cumberland Gap National Historical Park headwaters of Shilalah Creek , J. Robinson coll., 4-iv-2007, 5 larvae ( CUGA 4588 ) . Franklin County, Unnamed tributary at Camp Pleasant , J.K. Moulton coll., 8-v-2007, 1 male ( FAMU) . Vermont: Windsor County, Ascutney Notch , 200 yards from end of road , Weathersfield , T. Ames coll., 11-vi-2007, 1 female ( BYU) . West Virginia: Hardy County, 3 miles north-east of Mathias, Malaise trap, [N38°55 ̍, W78°49 ̍], D. Smith coll., 22-v-7-vi- 2007, 7 males, 3 females ( BYU) . [N38°33 ʹ 00.00″, W78°29 ʹ 24.00″], 21-v-2007, 1 male ( BYU) . Wyoming: Crook County, 3 ft. wide, clear mountain stream , Black Hills National Forest , R.J. Lavigne coll., 22-vii-1982, 2 males, 2 females ( BYU) . Sundance , gully at the edge of town , I-90, R.J. Lavigne and M. Pogue coll., 23-vi-1981, 1 male ( BYU) .

Figures

Figure 28. Polycentropus pentus Ross, 1941, 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 29. Polycentropus pentus Ross, 1941, female genitalia. A. left lateral; B. ventral.

Figure 50. Known Canadian province and US state distribution of Polycentropus pentus Ross, 1941, as indicated by grey shading.