Photuris pensylvanica, (DeGeer, 1774)

Heckscher, Christopher M., Lloyd, James E. & Branham, Marc A., 2022, Redescription of Photuris pensylvanica (DeGeer) (Coleoptera: Lampyridae) with the Designation of a Neotype, The Coleopterists Bulletin 76 (4), pp. 503-509 : 505-507

PHOTURIS pENSYLVANICA ( DeGeer, 1774)

Lampyris pensylvanica DeGeer 1774: 52–53 .

TYpe Specimens. Neotype (♂), here designated, placed in the National Museum of Natural History

(Smithsonian Institution), Washington, DC, USA (USNMENT01788002) : “ USA. Delaware ( NCCO). Wilmington Marsh. 39.721953, –75.561746. 2-VII-2015. DET & COL: C.M. Heckscher. ” An additional six specimens collected from the same locality and on the same date are deposited in the CMH Lampyridae collection currently housed at Delaware State University, Dover, DE, USA .

Diagnosis. This is a pale and diminutive Photuris ( Fig. 1 ) associated with freshwater tidal wetlands. Pronotal vitta has a wide base and apex creating an overall hourglass-shaped form. Pronotal orange pigmentation lacks red undertones. Elytra are structurally weak, often resulting in a noticeably curled or arched appearance after desiccation. Elytral tips are pointed, not broadly rounded, in comparison to some congeners. Elytral vittae engulf the humeri and fade posteriorly. Anterior one-fourth of elytra is often darker than posterior three-fourths. Scutellar shield and mesonotal plates are brown. Metacoxae are brown. Mean total length (n = 5): 9.5 mm ± 0.5 SD, range: 8.6–9.9 mm. Flash pattern: A two-part “dot-dash” emission consisting of a single short flash (~0.2 sec) immediately followed by a longer emission (~1.0–1.3 sec). Signal emitted while in flight with the dash typically given on a descent. The species is also thought to have an adjunct flash pattern of a single emission possibly given early in the evening, but this has been brought into question lately considering the confusion surrounding this taxon and the recent discovery of potentially sympatric single-flashing congeners (e.g., Photuris mysticalampas Heckscher , Photuris eliza Heckscher ). Behavior: Adults emerge after sunset and usually fly low among or slightly above emergent vegetation in coastal freshwater tide marshes or emergent vegetation among tidal swamp forests. May also sparsely inhabit non-tidal freshwater emergent marshes in coastal regions. The “dot-dash” signal is typically given on a descent and sometimes during a tumbling fall through dense vegetation.

NeotYpe Description. Head: Frons yellow or very slightly infuscate. Mandibles infuscate. Maxillary palpi gray. Clypeus amber, its apical edge black. Clypeal projections rather insignificant, middle projection most prominent. Clypeus bearing prominent setae. Vertex mostly yellow with an ill-defined broad brown crown. Antenna ( Figs. 1 , 2 ): Filiform. Brown with pale articulations. Rather short, ~0.45× length of body. Scutellar shield ( Fig. 3 ): Scutellar shield and mesonotal plates brown. Pronotum ( Fig. 3 ): Pronotum semicircular. Pale margins broad and mostly translucent. Posterior margin of pronotum slightly sinuate, lateral and anterior margins round- ed. Surface evenly punctate and covered uniformly in rather dense setae; pubescence denser and longer toward hind margin. Posterior lateral corners rounded, only slightly produced. Orange pigmentation circular, a rich dark orange without deep red undertones, with broad black central vitta. Vitta with apical tip broadly rounded with sharp demarcation toward outer edge continuous with edge of orange pigmentation and a protruding diffuse terminal tip nearly reaching terminal edge of pronotum. Shaft slightly constricted, serifs and flukes more diffuse. Serifs and flukes not well produced; rather, base of vitta broad, more rectangular in shape than anchor-like. Thus, vitta not arrowlike, more hourglass shaped. Total length of pronotum: 2.0 mm. Length along basal edge between two posterior corners: 2.5 mm. ElYtra ( Fig. 1 ): Pale brown with anterior one-fourth darker than posterior three-fourths. Vittae pale, the distal three-fourths almost imperceptible and extending about two-thirds length of elytra. Vittae engulf the humerus. Lateral margins somewhat broad, not reaching the apical tips, instead fading distally. Inner sutural margins quite pale, reaching both the apical tips and scutellar shield. Apical tips noticeably narrow and pointed. Total length: 7.8 mm. Total width at one-half length of elytra: 3.9 mm. Thorax: Meso- and metaventrites brown. Abdomen ( Fig. 4 ): First 3 visible ventrites (ventrites 1–3 or true abdominal segments II–IV; see Branham and Archangelsky [2000] for discussion regarding visible ventrite versus true abdominal segment number in Lampyridae ) brown, 4 (V) largely yellow, 5 (VI) and 6 (VII) yellow, 7 (VIII) pale and enclosing the aedeagus. Ventrite 6 (VII) only slightly emarginated. Legs ( Figs. 2 , 4 ): Hind legs long for a Photuris , ~0.80× length of body. Procoxa and mesocoxa pale yellow with some brown shading laterally. Metacoxa entirely brown. Trochanters pale yellow. Profemur with basal three-fourths pale, apical one-fourth brown. Meso- and metafemur pale yellow. Protibia mostly brown; meso- and metatibia largely yellow with slight infuscate areas bearing dark brown setae yielding an overall dusted appearance. Meso- and metatibia with two apical spurs of near equal length. Tarsi pale yellow with brown apical tips and blond setae. Claws pale yellow with amber points, anterior claws (of each pair) bifid, posterior claws simple. Aedeagus: Typical for a Photuris with no recognized diagnostic characters; consisting of a basal piece, two lateral lobes, and a central medial lobe with two lateral filaments (cf. Lloyd and Ballantyne 2003).

Variation Including NeotYpe (N = 5). Clypeus varies from amber to yellow. Antenna varies from ~0.35–0.55 length of body.Total length of pronotum: 1.9 mm ± 0.2 SD, range: 1.6–2.1 mm. Length along basal edge between two posterior corners: 2.4 mm ± 0.1 SD, range: 2.3–2.6 mm. Posterior broadened area of vitta varies in width relative to shaft but always more rectangular than anchor-shaped. Although most individuals are slender in appearance due to pointed apical tips, variation in width of lateral margins result in some specimens appearing oval in outline from above (large length-to-width ratio). Elytra in some specimens are somewhat translucent. Elytra total length: 7.4 mm ± 0.36 SD, range: 6.9–7.8 mm. Total width at one-half length of elytra: 3.8 mm ± 0.18 SD, range: 3.6–4.0 mm.

Figures

Fig. 1. Habitus of Photuris pensylvanica (neotype). Note pale bicolored elytra (anterior one-fourth darker than posterior three-fourths) with pale vittae fading posteriorly.

Fig. 2. Lateral view of Photuris penyslvanica (neotype). Note long legs, brown metacoxa and comparatively short antenna relative to body length.

Fig. 3. Scutellar shield and pronotum of Photuris pensylvanica (neotype). Note brown scutellar shield and hourglass-shaped pronotal vitta with a diffuse apical tip and a rectangular base.

Fig. 4. Ventral view of Photuris pensylvanica (neotype). Note brown metacoxa and pale trochanters.