Neoephemera eatoni, Holland, Victor B., Beaty, Steven R. & Jacobus, Luke M., 2016

Holland, Victor B., Beaty, Steven R. & Jacobus, Luke M., 2016, A new species of Neoephemera McDunnough, 1925 (Ephemeroptera: Neoephemeridae) from North Carolina and Virginia, Zootaxa 4138 (1), pp. 139-154 : 141-149

publication ID	https://doi.org/ 10.11646/zootaxa.4138.1.6
publication LSID	lsid:zoobank.org:pub:68B85686-A460-4989-A74B-0F6E97BF761B
DOI	https://doi.org/10.5281/zenodo.6072225
persistent identifier	https://treatment.plazi.org/id/AD3787FF-B34E-FFD6-FF34-FC97EA4BD480
treatment provided by	Plazi
scientific name	Neoephemera eatoni
status	sp. nov.

Treatment

Neoephemera eatoni , new species

( Figs. 1–10, 14, 18, 20–25 View FIGURES 18 – 22 View FIGURES 23 – 28 , 29 View FIGURES 29 – 30 , & 31–34)

= Neoephemera sp. B, McCafferty et al. (in press)

Description. Mature Nymph (preserved in 95% ethanol). Dimensions: Body length 8.1–11.8 mm; cerci and median filament ca. 0.7–0.8× body length. Body color: speckled brown and cream.

Head: Speckled brown with coronal and epicranial sutures pale. Dorsal diameter of compound eye 0.5 mm; one pale spot on left and right side of epicranial suture at base of each antenna ( Fig. 1). Antenna light brown at base, white medially to translucent at apex and length 0.8× width of head capsule; base of scape and head capsule forming triangular shape. Labrum ( Fig. 2 View FIGURES 2 – 8 ) with broadly rounded anteromedial notch with six short plumose setae along margin of notch and constricted arched row of 60 or more finely ciliated setae located dorsally, 100 µm from apicomedial margin; various sizes of plumose setae scattered posterior to arched labral setal row. Mandibles heavily mottled and sclerotized with stout bifurcate and plumose setae on outer margins ( Figs. 3–4 View FIGURES 2 – 8 ). Outer and inner incisors cleft on both mandibles with four and two denticles, respectively; prostheca bifid with sharp subapical spines; molars with reduced apical and subapical dissections. Hypopharyx ( Fig. 8 View FIGURES 2 – 8 ) with lingua apically truncate and covered with fine setae; superlinguae with two basal rows of sharp setae and covered apically with long hispid setae. Each galealacinia of maxillae with five distinct denticles ( Fig. 5 View FIGURES 2 – 8 ) and hispid setae at base and along remaining lacinial lateral margin. Segment I of maxillary palp slightly broader than segments II and III, with lengths of segments I–III= 0.3 mm + 0.2 mm + 0.3 mm ( Fig. 5 View FIGURES 2 – 8 ); labial palp (LP) segments I–III each with length of 0.3 mm; LP segment I slightly concave basally abutting basal segment of paraglossa and with dense plumose setae across ventral surface ( Fig. 6 View FIGURES 2 – 8 ). Paraglossa two segmented with dense hispid spines across ventral surface; glossa with similar setae ventrally ( Fig. 7 View FIGURES 2 – 8 ).

Thorax: Speckled yellowish brown to piceous; pronotal anteromedial dorsal tubercles absent, but with ridge extending diagonally from anteromedial submargin to anterior corners; pronotum and mesonotum with reduced anterolateral projections ( Figs 1 & 14 View FIGURES 9 – 17 ); hindwing pads small and covered by forewing pads in dorsal view. All legs subequal in length to each other; tibiae and tarsi lengths subequal on each leg ( Fig. 1) with adenticulate claws sharply curved, darkening to piceous at approximately 90 0 from vertex to apex ( Figs 1 & 9 View FIGURES 9 – 17 ); length ratio range of foreleg femur: tibia: tarsus: claw = 1.3–1.5: 1.0–1.1: 1.0: 0.4–0.5; midleg femur: tibia: tarsus: claw = 1.3–1.4: 1– 1.1: 1.0: 0.5; hindleg femur: tibia: tarsus: claw = 1.4–1.7: 1.0–1.2: 1.0–1.1: 0.5. Legs pale to brown, with distinct black spots present ventrally, at coxal-femoral junctions. Femora ( Fig. 9 View FIGURES 9 – 17 ) broader than tibiae and tarsi, with distinctive short bifurcate plumose setae in broad longitudinal row along medial dorsolateral surface ( Fig. 10 View FIGURES 9 – 17 ); submarginal dorsal surface with row of short plumose setae with few, scattered longer setae and ventral margin with full row of setae; tibiae and tarsi with scattered, apically fringed setae; dorsolateral surfaces of tarsi with rows of bifurcate, apically fringed setae. Thoracic sterna speckled yellow to brown, with blunt medial protuberances between fore and midcoxae.

Abdomen: Speckled yellowish brown to dark brown ( Fig. 1); terga I & II with distinct dorsomedial projections; terga with scattered bifurcate plumose setae on surfaces, with setae densely distributed along margins; well-developed apically pale posterolateral projections present on terga III–IX, with largest projection on tergum IX; terga VI–VII each with large, pale posteromedial spot ( Fig. 1). Terga VI–VIII with rudimentary posterormedial dorsal projections. Sternal coloration similar to terga, with distinct pale spots anteromedially on segments II–VIII. Terminal filament subequal in length to cerci, with whorls of spines at junction of each segment; intercalary setae longer, increasing in density from mid-length to apex.

Male imago (preserved in 95% ethanol). Dimensions: Body length 10.0– 10.5 mm; terminal filament and cerci lengths 10.1–10.5 mm.

Head: Compound eyes large, dorsal diameters 1.0 mm; separated by 0.25× width of one compound eye; yellow to light brown with purple outer margins. Vertex of head dark brown, with yellow paralleling eye margins. Ocelli large and yellow, surrounded by dark brown band at base, meeting anterolateral margins of compound eyes ( Fig. 29 View FIGURES 29 – 30 ); antenna pale to transparent, but with scape and pedicel white.

Thorax: Yellow to dark brown. Pronotum yellow and light brown medially; shaded to dark brown along posterior and lateral margins; emarginate posterior margin. Mesonotum lustrous dark brown with obovate anteronotal protuberance ( Fig. 29 View FIGURES 29 – 30 ); scutum dark brown; median notal suture and sutural ommation light brown; anterior parapsidal suture dark brown and posterior parapsidal suture yellow; scutellum yellow with two large dark brown ovate lateral spots and two smaller median triangular spots. Sterna yellow to dark brown; episternum dark brown; basisternum yellow to light brown; furcisternum dark brown with yellow median invagination. Metathorax dark brown laterally and yellow to light brown on remaining surface. Legs white, all femora with indistinct band at apex ( Figs. 23–25 View FIGURES 23 – 28 ); length ratios of foreleg femur: tibia and tarsal segment (TS) I: TS II: TS III: TS IV: TS V: claw = 1.0: 1.73 and 1.0: 8.0: 6.5: 6.5: 3.0: 1.5; length ratio of midleg femur: tibia: tarsus = 1.0: 0.76: 0.62; and length ratios of hindleg femur: tibia: tarsus = 1.0: 0.86: 0.57; all inner claws obtuse, and all outer claws pointed. Forewing length 9.2 mm and width 3.8 mm; hindwing length 2.5 mm and width 1.9 mm. Forewing hyaline with all longitudinal veins and crossveins pale; area between costal veins and border clouded, but with no distinctive markings on remainder of wing; single crossvein connecting A1 to hind margin ( Fig. 21 View FIGURES 18 – 22 ); A1 variable with one or two veinlets basally between CuP and A1; hindwing with acute costal projection basally ( Fig. 22 View FIGURES 18 – 22 ).

Abdomen: Segments VI–IX with bluntly pointed posterolateral projections directed ventrally. Terga I–VII translucent to white; terga VIII–X brown laterally; tergum X nearly all brown ( Fig. 18 View FIGURES 18 – 22 ). Small median spine on posteromedial margin of tergum II. Sterna I–VII translucent to white with distinct anteromedial purple spots; sterna VIII–IX white; sternum X mostly brown. Gentalia pale ( Fig. 20 View FIGURES 18 – 22 ); penes furcate with median ventral apical vshaped notch, not separated beyond subgenital plate; forceps segments I–IV lengths ratio = 1.0: 2.0: 0.3: 0.3. Cerci and terminal filament annulated on alternating segments.

Female imago (preserved in 95% ethanol). Dimensions: Body length 9.2–11.0 mm; terminal filament and cerci lengths 10.0– 10.5 mm.

Head: Brown; dorsal compound eye diameter 0.4 mm; compound eyes separated by distance of 1.0 mm; ocelli and antennae same as male.

Thorax: Yellow to brown; pronotom brown with posterior margin indented; mesonotum yellow along scutal sutures and sutural ommation, brown otherwise as in male; anteronotal protuberance same as male; sternum same as male but lighter brown. Foreleg length ratios of femur: tibia: tarsus = 1.0: 0.92: 0.85; midleg length ratios of femur: tibia: tarsus = 1.0: 0.85: 0.69; hindleg femur: tibia: tarsus length ratios = 1.0: 0.8: 0.57. All legs pale, with indistinct apical maculations on femora. Forewing length 10.2 mm and width 3.9 mm; hindwing length 2.7 mm and width 2.0 mm; wings with longitudinal veins and crossveins same as male ( Figs. 21–22 View FIGURES 18 – 22 ). Metathorax light brown.

Abdomen: Mostly brown speckled with light yellow spots dorsally; terga I–III light brown; terga IV–X with dark brown pigmentation increasing posteriorly; distinct longitudinal or lateral maculations absent. Sterna yellow with distinct purple spots posteromedially on segments I–VII and anterolaterally on segments II–VIII. Cerci and terminal filament annulated on alternating segments.

Egg. Length 180–190 µm; width 110–115 µm. Oval, rugose and without polar caps ( Figs. 31–32 View FIGURES 31 – 36 ); surface densely covered with fine threads, forming fibrous adhesive layer with numerous minute bumps, parallel ridges, and minute mushroom-shaped fibers (MF) ( Fig. 34 View FIGURES 31 – 36 ), together terminating in blunt finger-like projections (FP) scattered over surface of egg ( Figs. 31–34 View FIGURES 31 – 36 ). One or two tagenoform micropyles (TM) along equatorial region, with sperm guides 30–36 µm long and 17 µm wide.

Material examined. Type material. Holotype: ♂ imago (reared), associated exuviae, North Carolina, Rockingham Co., Dan River, NC 700, 36.4985, -79.6815, 16/V/2015, V.B. Holland [ NMNH]. Paratypes: One ♂ imago (reared), associated exuviae, ♀ imago (reared), associated exuviae, same data as holotype [ PERC]; one nymph (final instar), North Carolina, Dan River, off SR 1779, 36.48488, -79.7172, 9/IV/2015, V.B. Holland, M.D. Walters, L.E. Eaton [ CSUC]; one nymph (final instar), same data [ NCDWR]; one nymph (final instar), North Carolina, Mayo River, SR 1358, 36.53552, -79.9906, 1/V/2012, D.R. Lenat [ NCDWR].

Additional material. Two nymphs, Virginia, Craig Co., Sinking Creek, 15/V/1974, J. Wright [ CSUC]; two nymphs, Virginia, Grayson Co., New River, 6/VI/1973, J. Wright [ CSUC]; nine nymphs, North Carolina, Rockingham Co., Dan River, off SR 1779, 36.48488, -79.7172, 28/X/2014, V.B. Holland, E.D. Fleek, M.D. Walters, L.E. Eaton, R.W. Smith, M.J. Stillwell [ NCDWR]; seven nymphs, ♀ imago (reared), North Carolina, Dan River, off SR 1779, 36.48488, -79.7172, 9/IV/2015, V.B. Holland, M.D. Walters, L.E. Eaton [ NCDWR]; three nymphs, ♂ imago (reared), ♀ imago (reared), ♂ subimago (reared), ♀ subimago (reared), North Carolina, Dan River, off SR 1779, 36.48488, -79.7172, 7/V/2015, V.B. Holland [ NCDWR]; one nymph, ♂ imago (reared), two ♀ imagos (reared), ♂ subimago (reared), Rockingham Co., North Carolina, Dan River, NC 700, 36.4985, -79.6815, 16/V/2015, V.B. Holland [ NCDWR]; one nymph, Rockingham Co., North Carolina, Mayo River, NC 770, 36.47083, -79.9514, 30/III/1989, L.E. Eaton, D.R. Lenat, M. Wicker [ NCDWR]; three nymphs, Rockingham Co., North Carolina, Mayo River, SR 1358, 36.53552, -79.9906, 18/V/2015, S.R. Beaty, V.B. Holland, M.J. Stillwell [ NCDWR].

Etymology. We are honored to name this species after Larry E. Eaton (North Carolina Division of Water Resources) in recognition of his long-term contributions to the study of aquatic macroinvertebrates as indicators of water pollution. He was one of the first biologists to observe and collect this species in its unique habitat.

Diagnosis. Neoephemera eatoni nymphs have been collected together with N. youngi . Neoephemera eatoni nymphs and imagos will key to N. youngi in Berner (1956) and Bae & McCafferty (1998) with the exception of imagos lacking distinct bands apically on femora and the absence of purplish-gray banding on tarsal segments II– IV presented in couplet 2 of Berner (1956). However, N. eatoni can be distinguished easily from all described North American Neoephemera species by the following combination of characters. In the nymph: (1) short robust legs; lengths of forelegs, midlegs, and hindlegs are subequal to each other and tibial to tarsal length ratios are subequal on all legs ( Figs 1 & 9 View FIGURES 9 – 17 ); (2) tarsal claws sharply curved ( Fig. 9 View FIGURES 9 – 17 ); (3) anterosubmedian tubercles absent on the pronotum; (4) rudimentary pronotal anterolateral projections and broadly rounded reduced mesonotal anterolateral expansions ( Figs 1 & 14 View FIGURES 9 – 17 ).

In addition to the above characters, nymphal setae characters separating N. eatoni from N. youngi include: (1) shorter bifurcate plumose setae ( Figs 9–12 View FIGURES 9 – 17 ) in a broad longitudinal row along medial dorsolateral surface on all femora ( Figs 9–10 View FIGURES 9 – 17 ); (2) denser plumose setae on the first segment of the labial palps ( Fig. 6 View FIGURES 2 – 8 ); (3) a constricted arched row of 60 or more hispid setae situated dorsally 100 µm distal to the apicomedial labral notch margin ( Fig. 2 View FIGURES 2 – 8 ). In N. youngi , this arched row of setae is less constricted and situated 50 µm distal to the apicomedial labral notch margin.

In the imago, this species shares the presence of annulated caudal filaments with N. youngi ; however, it is easily distinguished by the following characters: (1) unique dorsal maculation in males ( Fig. 18 View FIGURES 18 – 22 ) and females; (2) males with fore tibia at least 2× the length of mid and hind tibiae ( Figs 23–25 View FIGURES 23 – 28 ), female leg lengths are subequal to each other; (3) absence of distinct leg banding; (4) obovate anteronotal protuberance on the mesothorax ( Fig. 29 View FIGURES 29 – 30 ).

In the eggs, this species is separated from N. youngi by the presence of apically blunt finger-like projections rather than mushroom-shaped projections ( Figs 31–36 View FIGURES 31 – 36 ).