Polycentropus alabamensis Hamilton, Harris, and Lago, 1990

Orfinger, Alexander Benjamin, 2023, Taxonomic revision of the Polycentropus confusus species group (Trichoptera: Polycentropodidae), Journal of Natural History 57 (41 - 44), pp. 1825-1916 : 1834-1836

Polycentropus alabamensis Hamilton, Harris, and Lago

( Figures 5–6 , 37 )

Polycentropus alabamensis Hamilton, Harris, and Lago, 1990: 363–365 , fig. 1, J; type locality ′ United States: Alabama: Lawrence Bee Branch below falls, Bankhead National Forest ̍ ( USNM, lost) .

Polycentropus new species 12 Hamilton 1986: 70–71, fig. 4.2, J.

Polycentropus n. sp. (nr. elarus ) Lago and Harris 1987: 258.

Diagnosis. Males of this species are most similar to those of P. elarus in the apical narrowing of the inferior appendages,the shape of the basodorsal process of the inferior appendage, the similar shape of the pre-anal appendages, and the sinuate curvature of the dorsal process of the pre-anal appendages. Polycentropus alabamensis can readily be distinguished from P. elarus and all other members of the P. confusus species group by the following combination of characters: prominent, acute, posteroventral point on each pre-anal appendage, the apicodorsal emargination forming a caudal spur visible on the dorsobasal process of each pre-anal appendage, the tapered, incurved apex of the intermediate appendages, and the tapered, strongly incurved apex of the inferior appendages in ventral view.

Females of P. alabamensis are distinguished from those of all other species in the P. confusus species group by reniform wrinkled interior parts of gonopods VIII, by the posterior apex of external parts of gonopods VIII with a deep mesal emargination and appearing bifid in ventral view, and by the unique shape of segment IX bearing bilateral acute, horn-like processes.

Adult description

General. Length. of male 6.9–7.8 mm (mean = 7.3 mm; n = 5). Length of female 8.2– 9.0 mm (mean = 8.5 mm; n = 3).

Male genitalia ( Figure 5A–E ). Abdominal segment VIII annular. Abdominal sternite IX large, semicircular in lateral view, anterior margin round, posterior margin nearly straight; in ventral anterior margin deeply emarginate. Intermediate appendages originating beneath terga IX+X and extending beyond them, curved gradually caudoventrad, their apices each bearing 5 small setae; distally extending beyond tergum X, apices each bearing 5 small setae; in lateral view curved slightly ventrad; in dorsal view apices proximate, subparallel. Body of pre-anal appendages short, with prominent sharp point, posteroventral in lateral view; in lateral view dorsal process moderately sinuate, decurved basally, distally, with apicodorsal emargination forming caudal spur; in dorsal view slender, elongate, moderately sinuate, subparallel. Inferior appendages in lateral view each with elongate ventral portions, in lateral view tapering slightly to apex, extending to apex of intermediate appendage, in ventral view greatly tapered beyond mid-length with apex acute, strongly curved mesally; basodorsal process prominent, erect, in lateral view neck long and thin, enlarged apex goose-head shaped with acute ventrally directed point, in caudal view blunt projection projecting downward. Phallus in lateral view tubular, moderately decurved, broadened apically, basally, with mesoventral concavity, internal spinules absent; internal phallic sclerite in lateral aspect moderately long, enlarged slightly distally, with tapered anterior portion.

Female genitalia ( Figure 6A–B ). Venter VIII in ventral view with ventral plates short, subparallel to subtly divergent, semi-elliptical, tapered, laterally recurved, 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 round with two apical lobes separated by deep mesal emargination; in lateral view extending posterad beyond ventral plates in round process; segment IX in ventral view with diagonal mesolateral emarginations forming acute horn-like processes, in lateral view produced caudodorsad, evenly tapered to acute apex extending beyond ventral plates; internal parts of gonopods VIII in ventral view visible through venter VIII even in uncleared specimen, appearing longitudinally wrinkled, darker than surrounding tissue, subparallel to subtly divergent, reniform, with acute posterior apices distinctly anterior of apices of ventral plates, caudolateral margins sinuous; in ventral view anterior part of genital chamber sclerotised, subtrapezoidal, base overlapping with sclerotised margin of segment IX; processus spermathecae subovoid with central elevation bearing opening of ductus spermathecae.

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

Pupa. Unknown.

Notes. The type series is lost. Specimen USNMENT01819507 is herein designated as the neotype for Polycentropus alabamensis .

Biology. This species is most commonly collected in small streams of the Cumberland Plateau physiographic region and occasionally from the Coastal Plain physiographic region. Adults have been collected using UV light traps from April to September and late-instar larvae taken from cool, clear, flowing streams with rocky substrate in April.

Distribution ( Figure 37 ). USA: Alabama.

Material examined. Neotype: USA. Alabama: Fayette County, Little Tyro Creek , [N33° 35 ʹ 20.76″, W87°29 ʹ 47.04″], A. Orfinger coll., 3-v-2021, 1 male (USNMENT01819507) . Non-type material: USA . Alabama: Bibb County, Rocky Branch, S .C . Harris and S . Hamilton coll ., 12-vi-1991, 1 male ( FAMU) . Rocky Branch at USGS Gage , 1 male ( FAMU) . Fayette County, Headwaters of Wallace Branch , UV light, [N33°38 ʹ 16.80″, W87°31 ʹ 40.80″], A . Orfinger coll ., 4-iv-2022, 5 males ( FAMU), 3 females ( FAMU) . Wallace Branch at headwaters, [N33° 37 ʹ 44.76″, W87°31 ʹ 15.96″], 3-v-2021, 3 males ( FAMU) . Franklin County, Dismal Wonders Garden , Dismal Branch, S . Harris coll ., 2 vi-1983, 1 male ( FAMU) . Morgan County, Hughes Creek , light trap, [N34°24 ʹ 38 ̍, W86°37 ʹ 07 ̍], B . Dinkins coll ., 19-ix-2020, 2 males ( FAMU) . 2 males ( FAMU) . Spring outside of Curry Cave , 6-7-iv-2020, 2 larvae ( FAMU) . Winston County, Bankhead National Forest, small tributary of West Sipsey Fork , west side of river 100 m downstream of CR-60 bridge, 9.5 miles north of Double Springs , UV-black light pan trap, A .K . Rasmussen coll ., 24-v-2003, 1 male ( FAMU) .

Figures

Figure 5. Polycentropus alabamensis Hamilton, Harris, and Lago, 1990, male genitalia (neotype). 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 6. Polycentropus alabamensis Hamilton, Harris, and Lago, 1990, female genitalia. A. left lateral; B. ventral.

Figure 37. Known Canadian province and US state distribution of Polycentropus alabamensis Hamilton, Harris, and Lago, 1990, as indicated by grey shading.