Synanthedon nielseni Taft and Cognato, new species urn:lsid:zoobank.org:act: 4464FD3C-25A5-47C4-A5A1-7E833136A20D Fig. 2A, B, C Type material. Holotype: Male, South Carolina: Charleston Co., north of McClellanville in the Santee Coastal Reserve, at light, 14 August, 2023, Coll. Eric LoPresti (A.J. Cook Arthropod Research Collection, Michigan State University, East Lansing, MSUC). Paratypes: 3 males, South Carolina: Charleston Co., east of McClellanville, Wedge Plantation, at light. (Richard B. Dominick collection at University of South Carolina); 1 male, Alabama, Chelsea, at light, Coll. John Morgan (MSUC). Diagnosis. Synanthedon nielseni sp. nov. is most similar in appearance to S. arkansasensis but can be differentiated by abdominal color pattern and male genitalic differences. The abdominal dorsal segments of male S. nielseni sp. nov. are glossy black with yellow on the posterior edges of tergites two, three, four, six and seven (widest on four) and tergite 5 is black only (fresh specimens may have a few yellow scales on the posterior of tergite 5) (Fig. 2A, B). The abdomen of S. arkansasensis is blue-black except segment one with yellow on the posterior edges of all tergites (Fig. 2D, E). The sternites of segments six and seven are black in S. nielseni sp. nov. and are completely banded in yellow in S. arkansasensis. As for the S. nielseni sp. nov. male genitalia, the valve is longer and much thinner that S. arkansasensis with crista succuli ~1/3 length of valve (Fig. 2C). Additionally, the saccus ridge is shorter and much less distinct in the S. nielseni where S. arkansasensis (Fig. 2F) has a very prominent saccus ridge that is without setae at the apex. Description. Male (Fig. 2A, B) Head with vertex black with a few dark orange-brown scales mixed within; frons translucent grey with white laterally; occipital fringe yellow; labial palpus smooth, yellow; antennae black. Thorax black, laterally yellow, with inner margin of tegula yellow with elongated scales; metathorax yellow dorsally with brown-black hairlike scales mixed with a few pale brown and yellow hairs emanating laterally behind the wing bases with yellow scaling beneath wing. Forewing mostly hyaline with brown-black outer margin and orange or red-orange apically between veins, discal spot short and small, pale brown-black with red-orange along the distal edge. Hindwing hyaline with narrow dark brown margins and fringe. Forelegs with bi-colored coxae with black mesially and yellow distally, femur black on the fore and hindlegs; femur of midleg yellow with black distally with yellow spurs; tibia of hindleg yellow including tibial spurs; outer side proximally and distally black, tarsus yellow with black spines ventrally. Abdomen blue-black on segment one with yellow laterally, other segments glossy black, posteriorly edged yellow on tergites two, three, four, six and seven (widest on four), tergite 5 is black (fresh specimens may have a few yellow scales on the posterior edge of tergite 5), sternites two to five with yellow bands, lateral yellow marks on 6 and 7; anal tuft black edged with yellow-orange laterally and orange tuft ventrally. Genitalia (n= 2), crista succuli <1/3 length of valve, saccus ridge short, nearly indistinct (Fig. 2C). Female. Unknown but images on BugGuide.com and iNaturalist.com suggest they are akin to the males however we are not aware of any female specimens available for dissection and DNA analysis. Host. Unknown but the species was associated with a mixed habitat of live oak (Quercus virginiana), sweetgum (Liquidambar styraciflua), redbay (Tamala borbonia), cypress (Taxodium distichum & T. ascendens), black tupelo (Nyssa sylvatica), longleaf pine (Pinus palustris) and wax myrtle (Morella cerifera), with other mixed woody plants, in coastal South Carolina and oak forests in Alabama. Distribution. Identified specimens were collected only in South Carolina and Alabama with additional male Synanthedon nielseni sp. nov. images from Maryland, Virginia, Tennessee, Georgia, Florida (BugGuide.com and iNaturalist.com). Etymology. The species is named after Mogens C. Nielsen, an original member of the Lepidopterists’ Society, an authority on Michigan’s lepidopteran fauna and the author of the “Butterflies of Michigan ”, a long-time environmental specialist for the Michigan Department of Natural Resources, a mentor to numerous naturalists and scientists including WHT and a great friend to many. Remarks. Recent review of the color plates of clearwing moths of Florida (Brown & Mizell 1993) suggest that the image of S. arkansasensis is likely S. nielseni sp. nov.

Published as part of Jr, William H Taft, Lopresti, Eric F. & Cognato, Anthony I., 2025, A new species of Synanthedon Hübner (Lepidoptera: Sesiidae) from the coastal South Carolina and central Alabama, United States, pp. 294-300 in Zootaxa 5686 (2) on pages 296-298, DOI: 10.11646/zootaxa.5686.2.8, http://zenodo.org/record/16985786