Polycentropus dinkinsorum Orfinger and Etnier, 2020

Orfinger, Alexander Benjamin, 2023, Taxonomic revision of the Polycentropus confusus species group (Trichoptera: Polycentropodidae), Journal of Natural History 57 (41 - 44), pp. 1825-1916 : 1864-1866

Polycentropus dinkinsorum Orfinger and Etnier

( Figures 20 , 45 )

Polycentropus dinkinsorum Orfinger and Etnier, 2020: 127–129 , fig. 1, J; type locality ′ North Carolina: Henderson County, Flat Rock, Carl Sandburg Home National Historic Site, [N35°16 ʹ 16.28, W82°27 ʹ 01.04 ̍]″ ( USNM) .

Diagnosis. The males of P. dinkinsorum can be distinguished from those of all other members of the P. confusus species group by the sharp angulate, tooth-like projection of the posteroventral margin on the body of the pre-anal appendage. Male genitalic structure is most similar to that of P. carolinensis and P. carlsoni . However, it can readily be distinguished from both P. carolinensis and P. carlsoni by the more pronounced mesoventral swelling on the phallus, the longer necks of the basodorsal process of the inferior appendages, and the more obtusely curved heads of the basodorsal processes of the inferior appendages. Males can also be distinguished from P. carlsoni by the slight downward curvature of the phallus, vs the stronger curvature exhibited by P. carlsoni . From P. carolinensis , it can also be distinguished by the presence of a distinctly pronounced, horn-like, apical projection of the combined terga IX+X extending caudad over the intermediate appendages. From P. floridensis , P. pentus and P. vernus , which each exhibit a ventral swelling on the phallobase, males of P. dinkinsorum can easily be distinguished by the more distal location of the mesoventral swelling, and the shape of the basodorsal process of each inferior appendage. From P. floridensis and P. vernus , P. dinkinsorum can be distinguished by the presence of the acute, tooth-like projection of the posteroventral margin of the pre-anal appendage, and from P. pentus by the prominent profile of this projection (set in a concavity in P. pentus ).

Adult description

General structure. Length of male 6.1–7.2 mm (mean = 6.5 mm; n = 4).

Male genitalia ( Figure 20A–E ). Abdominal segment VIII annular. Tergum IX fused with segment X, membranous, caudally extended as horn-like projection in lateral view. Sternum IX round in lateral view, posterior margin lobate. Intermediate appendages positioned beneath terga IX+X, distally extending beyond tergum X, apices each bearing 3 small setae; in lateral view curved slightly ventrad; in dorsal view apices proximate, parallel. Pre-anal appendages triangular in lateral view, each with posterior angle acute, forming tooth-like projection; in lateral view dorsal process wide basally, distally slender, process curved ventrad terminating in slender spine; in dorsal view, sub-parallel, slender, elongate. Inferior appendages each with ventral portion in lateral view gradually tapered, extended posterad slightly beyond intermediate appendages, ventral margin nearly straight; in ventral view, mesal projection near mid-length, distal half curved inward; basodorsal process in lateral view erect, with long neck terminating in short, round head projecting downward, in ventral view completely hidden by main body of inferior appendage, head round, oriented medially, in caudal view slightly round, curved downward. Phallus in lateral view slightly curved ventrad, mesoventral swelling arising near mid-length, apical section rectangular, internal spinules absent, internal phallic sclerite moderately elongate with narrow distal portion.

Female genitalia. Unknown.

Larva. Unknown.

Pupa. Unknown.

Biology. Almost nothing is known of the biology of this recently described species. Polycentropus dinkinsorum has been collected near cool, rocky streams of the southern Appalachian Mountains from May to September. Collection of specimens via both Townes-style Malaise trap ( Townes 1962, 1972) and UV light trap suggests both diurnal and crepuscular flight activity, respectively.

Distribution ( Figure 45 ). USA: North Carolina , Tennessee, West Virginia.

Given that this species is currently known from the Appalachian Mountains of North Carolina , Tennessee, and West Virginia, it is likely to eventually be recorded from eastern Kentucky and western Virginia.

Material examined. Holotype: USA. North Carolina : Henderson County, Flat Rock, Carl Sandburg Home National Historic Site, Malaise trap, [N35°16 ʹ 16.28″, W82°27 ʹ 01.04″], I. Hoff and E. Eleantar coll., 20-ix-2012, 1 male (USNMENT 01350618) . Paratypes: USA. North Carolina : Henderson County, Carl Sandberg Home National Historic Site , Flat Rock, Duck Pond, Malaise trap, [N35°16 ʹ 15.96″, W82°27 ʹ 01.04″], I . Hoff and E . Eleantar coll ., 16–24- v-2012, 1 male ( ROME184984 ) . Swain County, Great Smoky Mountains National Park, Kephart Prong Trail near trail head across from bridge over Oconaluftee River , black light trap, 834 masl, [N35°35 ʹ 11.52″, W83°21 ʹ 32.87″], B . Sullivan coll ., 23–2vii-2000, 1 male ( INHS Insect Collection 923,902) . 1 male (USNMENT 01350619). 1 male ( FAMU) . West Virginia: Raleigh County, Piny Creek tributary, New River system, [N37°50 ʹ 39.08″, W81°06 ʹ 48.88″], G . R. Dinkins, B .J . Dinkins , and H .O. Faust coll ., 2vi-2014, 1 male ( CUAC000107314 ) .

Non-type material. USA. North Carolina : Haywood County, Great Smoky Mountains National Park, Mt . Sterling Trail, D. Paulsen coll ., 27-vi-1989, 9 males ( ECC 3.269 ) . Tennessee: Blount County, Sams Creek, 100 m below Thunderhead Creek , D . Etnier coll ., 7-vi-1996, 1 male, 1 pupa, 1 larva (includes early instar larva broken in two and pupa) ( ECC 3.288 ) . Carter County, Roan Mountain State Park , black light, J . Ensminger coll ., 6–12-viii-2000, 1 male ( ECC 3.357 ) .

Figures

Figure 20. Polycentropus dinkinsorum Orfinger and Etnier, 2020, 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 45. Known Canadian province and US state distribution of Polycentropus dinkinsorum Orfinger and Etnier, 2020, as indicated by grey shading.