Scirtes goodrichi Springer and Waller, 2021

Springer, Charles A. & Waller, Deborah A., 2021, A new species of Scirtes Illiger, 1807 (Coleoptera: Scirtidae) from Virginia and South Carolina, U. S. A., Insecta Mundi 2021 (882), pp. 1-9 : 3-7

Scirtes goodrichi Springer and Waller , new species

Diagnosis. Scirtes goodrichi ( Fig. 1 ) is distinguished from the five other species of Scirtes in our area by the following combination of characters that define this species: head width over 2.31 times head length; antennomere II arises from apex of I; clypeus with anterolateral angles not recurved; head, pronotum and proepisternum dark, without white, tan or orange markings; length of elytra 4.10–5.58 times mid-elytral height; elytra never vittate but usually with orange-brown sutural stripe; lateral margin of elytra slightly explanate, width of turned-out rim less than width of protibia; shape of prosternal process, male genitalia, tergite VIII (except S. orbiculatus ) and female prehensor also species specific.

Scirtes goodrichi without elytral stripe resemble the general habitus of S. tibialis but can be distinguished externally by the clypeal anterolateral margins not recurved, head width over 2.31 times head length; long overlapping mandibular teeth, and shape of prosternal process. Internally, S. goodrichi differ markedly from S. tibialis by the male genitalia, male tergites VIII and IX and female prehensor ( Fig. 2 ). If a completely dark or melanistic phase of S. orbiculatus is found, yet unknown to the authors, differences in elytral convexity, body length to width ratio and shape of prosternal lateral aspect will separate them from S. goodrichi externally, differences in male genitalia, male tergite IX, and female prehensor will separate them internally. Scirtes goodrichi is most closely related to S. orbiculatus based on similarities of the clypeus, head width to head length ratio, mandibular tooth size, elytral stripe, male genitalia, male tergite VIII, and female prehensor.

Description of holotype. Body. Elongate oval, elytra slightly convex, head and pronotum deflexed in normal relaxed position, length from anterior margin of pronotum to apex of elytra 2.75 mm, width across both elytra 1.69 mm, length 1.62 times width. Head width across both eyes 0.83 mm, pronotum width across posterior margin 1.28 mm, pronotum 1.54 times wider than head, elytra 1.32 times wider than pronotum. Maximum lengths: head from anterior margin of clypeus to base of eyes 0.35 mm; pronotum 0.51 mm; elytra 2.38 mm; total maximum length 3.24 mm; total length 1.92 times width. Coloration. Entire dorsum shiny, dark brown except for an orange-brown longitudinal stripe on the middle 1/3 of the elytral suture, not extending outward over disc, width of stripe subequal to one dorsal eye width on each elytron, color and width of stripe decrease anteriorly and posteriorly. Prosternum, mesosternum, metasternum, all coxae and femora brown; abdominal sternum with irregular areas of dark and light brown. Proepisterna and elytral epipleura light brown. All palps, tibiae and tarsi light brown to stramineous. Antennomere I brown, II–VIII light brown, IX–XI fuscous. Punctation. Setigerous punctures on head, pronotum and scutellar shield very fine, subequal in size to one eye facet diameter; head punctures separated by one to three puncture diameters; punctures on pronotum and scutellum separated by 3–5 puncture diameters, areas between punctures smooth, shiny. Elytral punctures larger, equal in size to 3 eye facet diameters, separated by one-half to one puncture diameter, producing a coarser surface than on head and pronotum. Vestiture. Most setae on dorsum pale yellow and semi-erect; setae on head directed forward, setae on pronotum and scutellar shield directed backward, all above setae subequal in length to width of prothoracic tarsomere I; setae on elytra directed backwards, longer, subequal in length to width of metathoracic tarsomere I. Setae on venter and appendages shorter than on head, pale yellow and recumbent. Head. Deflexed, inserted into prothorax to base of eyes, wider than long, width across eyes 0.83 mm, length from anterior margin of clypeus to posterior margin of eyes 0.35 mm, width 2.38 times length. Dorsal interocular distance 0.51 mm, dorsal eye width 0.16 mm, dorsal interocular distance 3.2 times one dorsal eye width. Eyes dark grey in middle with argenteous rim two to three eye facets wide. Subocular carina well developed under entire eye, carina height equals two to three eye facet diameters. Clypeus with lateral margins straight and directed anteriorly, anterolateral angles rounded, anterior margin slightly emarginate, width 14 times longer than depth. Antennae filiform, 1.24 mm long, 1.49 times width of head across eyes, and 0.45 times body length. Antennomere II attached to apex of I, antennomeres I to III decrease in size, III is the smallest overall, IV to X subequal, XI longest. Pronotum. Slightly deflexed, trapezoidal, very transverse, 0.51 mm long at midline, anterior margin 0.86 mm wide, posterior margin 1.28 mm, posterior margin width 2.5 times length; anterior margin broadly emarginate, lateral margin slightly convex, angles backward at about 114 degrees, posterior margin sinuate, pronotal width 1.54 times head width. Thorax. Length of prosternal process equal to but does not exceed apices of procoxae; metathoracic femur enlarged, saltatorial, length 1.84 times width, compared to mesothoracic femur length 2.58 times width; metatibial long spur 2.6 times longer than short spur; metatibial long spur 1.0 times metatarsomeres II–V combined length. Metatarsomere 1 length 1.3 times metatarsomeres II–V combined length. Elytra. Length 2.38 mm, width across both elytra 1.69 mm, length 1.41 times width; elytral width 2.03 times head width; elytral width 1.32 times pronotal width; elytral height at middle 0.56 mm; length 4.25 times longer than height (convexity); lateral margin slightly explanate, greatest width of turned-out rim on anterior 1/3 equals width of antennomere IV, reduced posteriorly; elytral epipleuron width subequal to one dorsal eye width on anterior 1/3, reduced posteriorly. Scutellar shield. Triangular, width 0.32 mm, length 0.22 mm, width 1.43 times length. Abdomen. Fifth visible abdominal sternite emarginate, 0.24 mm wide, 0.04 mm deep, width 6.0 times depth. Female prehensor. The female prehensor (bursal sclerite) ( Fig. 2 ) has two pairs of processes directed anteriorly, one pair directed posteriorly and a single tooth at the dorsal midline directed anteriorly. Prehensor width 0.40 mm, width across both elytra 1.69 mm, elytral width 4.23 times prehensor width.

Type material. A total of 24 specimens was examined, 17 from the type locality, 9 males and 8 females, all dissected. The 7 specimens from South Carolina included 3 males and 4 females, all dissected. HOLOTYPE. Female : labeled, “VA:Norfolk 19-V-2017 C.A. Springer ”/” UV Light”/red label “ HOLOTYPE Scirtes goodrichi Springer & Waller ”. Deposited in National Museum of Natural History, Washington, DC. TYPE LOCALITY. 1300 Cloncurry Road , Norfolk, Virginia 23505 (36.91361111 °N, 76.31416667 °W). Elevation: 3.0 m. ALLOTYPE. Male: labeled “VA: Norfolk 3-VIII-2020 C.A. Springer ”/” UV Light”/blue label “ ALLOTYPE Scirtes goodrichi Springer & Waller ”. Deposited in the National Museum of Natural History. Allotype locality same as holotype. PARATYPES. The following paratypes from Norfolk, Virginia all share the type locality, collector, collection technique, and are deposited in NMNH. The genders and collection dates are as follows: 1 female 28-V-2011 ; 1 female 31-V-2013 ; 1 female 28-VIII-2013; 1 female 11-VI-2014, 1 male 17-VI-2014; 1 female 18-VI-2014 ; 1 female 3-VII-2014; 1 male 29-VII-2014; 1 female 24-VI-2020; 1 male 12-VII-2020; 1 male 3-VIII-2020; 1 male 11-VIII-2020; 1 male 12-VIII-2020; 1 male 18-VIII-2020; 1 male 22-VIII-2020. South Carolina: the next four specimens share the following collection data: “ USA: SC: Georgetown Co. 33.3302 °N, 79.2469 °W Baruch/Hobcaw Barony VII.9.2015 M. Caterino & A. Deczynski ” ; 1 male “Clemson University 13450”, CUAC ; 1 male “Clemson University 13021”, CUAC ; 1 male “Clemson University 13275”, CUAC ; 1 female “Clemson University 13023”, CUCA ; 1 female “SC: Berkeley Co. Cypress Gardens PIN-V-8/9-98”/”At U. V. Light”/” Coll. J.C. Ciegler ”, CUAC ; 1 female “Moncks Corner, S.C. 9/17/2004 ”/”At U. V. Light ”/” Coll. J.C. Ciegler ”, JCC ; 1 female “Moncks Corner, S.C. 5/8/98”/”At U. V. Light ”/” Coll. J.C. Ciegler ”, JCC. All specimens with yellow paratype labels, “ PARATYPE Scirtes goodrichi Springer & Waller ” .

Geographical range. Known from only two states, S. goodrichi first came to our attention with specimens from the type locality in Norfolk, Virginia, that eventually totaled 17. Loans from Clemson University and Janet Ciegler’s personal collection yielded seven more specimens from eastern South Carolina, including one location in Berkeley County and one location in Georgetown County.

Etymology. The species is named for the late Michael Goodrich, Eastern Illinois University, Charleston, Illinois, the senior author’s friend and research associate from 1961–2015. The name is a masculine noun in the genitive case.

Range of intraspecific variation. Body. Smallest specimen: male, Georgetown Co., South Carolina, VII.9.2015, 33. 3302 °N 79. 2469 °W, Baruch/Hobcaw Barony, M. Caterino & A. Deczynski, Clemson University 13021. Largest specimen: female, VA: Norfolk, 11-VI-2014, C. A. Springer. Size range in normal deflexed position from anterior margin of pronotum to apex of elytra; body length 2.39–3.10 mm, width across both elytra 1.63–1.97 mm, length 1.47–1.65 times width. Head width across both eyes 0.77–0.88 mm, pronotal width across posterior margin 1.20–1.38 mm, pronotal width 1.52–1.62 times head width, elytral width 1.30–1.47 times pronotal width. Coloration. Base color dorsally ranges from brown to black. Width of orange-brown sutural stripe varies from two dorsal eye widths on each elytron to completely absent. Head. Clypeal emargination 13–25 times wider than deep; dorsal interocular distance 2.75–3.75 times one dorsal eye width; subocular carina height equals one to three eye facet diameters, more strongly developed laterally than medially; antennal length 1.07–1.28 mm, antennal length 1.31–1.66 times head width, body length 1.95–2.70 times antennal length, elytral width 2.03–2.36 times head width; eye color highly variable, can be all argenteous, black, grey or magenta; bicolored eyes include a background of the previous colors with contrasting spots or variegations, or black with argenteous or magenta rim. Mouthparts. Labrum 1.90–2.20 times wider than long, anterolateral angles broadly rounded, anterior margin slightly convex. Mandibles unidentate ( Fig. 3 ), tooth length equals 1/4–1/3 greatest width of mandible, teeth overlap each other (left over right) in closed position, denticles absent. Maxillary palps with 4 palpomeres, I shortest, II widest of all and usually slightly longer than, or subequal to III; IV longest, 1.25 times longer than II, attenuate at apex. Labial palps with 3 palpomeres, I shortest, II longest, more than 2 times longer than I and 1.25 times longer than III, III arises subapically from middle of II on medial side, II and III rounded at apex, all palpomeres subequal in greatest width. Thorax. Prosternal process ( Fig. 4 ) with anterior margin convex, posterior margin concave, both converging posteriorly to a rounded apex, length of prosternal process equal to, but does not exceed, apices of procoxae; metafemoral length 1.76–1.97 times width; metatibial long spur length 1.97–2.60 times short spur length; metatibial long spur length 0.69–1.16 times metatarsomeres II–V combined length; metatarsomere 1 length 1.23–1.48 times metatarsomeres II–V combined length; all femora and tibiae can be lighter in color at both ends, as well as all trochanters. Elytra. Elytral length 4.10–5.58 times mid-elytral height (convexity). Scutellar shield. Triangular, range of width 0.27–0.32 mm, range of length 0.22–0.25 mm, width 1.16–1.50 times length. Abdomen. Emargination of 5th abdominal sternite, width for males 4.6–8.6 times depth and females 5.8–15.0 times depth. Secondary sex characters. No secondary sex characteristics were recognized. Male genitalia. The aedeagus is composed of an outer tegmen ( Fig. 5–6 ) surrounding the inner penis ( Fig. 7–8 ). Tegmen laterally flattened, with two lateral lobes (parameres) directed posteriorly and a dorsal strut directed anteriorly, tegmen closed dorsally, open ventrally. The penis is composed of a large supporting basal body (pala) with two movable processes directed posteriorly. The median lobe (parameroid) arises subapically from the right side of basal body, with a large apical tooth directed dorsally, tooth is 1.0–1.7 times width of median lobe. The serrate process (trigonium) arises apically from the left side of basal body, with a row of 15–18 small ventral teeth, apex rounded, without large apical tooth. Males dissected, 12. Male tergites VIII and IX. Male tergite VIII ( Fig. 9 ), has two longitudinal apodemes that curve ventrally at apex, connected by a cross-bar at their midpoint, these three rods support an apical membrane between them with posterior margin deeply concave; tergite IX ( Fig. 10 ) has two longitudinal apodemes supporting an apical membrane, with posterior margin convex, anterior margin concave. Tergite VIII is different from all other Scirtes in our area except S. orbiculatus , and tergite IX is unique among Scirtes . Female prehensor. The female prehensor (bursal sclerite) ( Fig. 2 ) is a well sclerotized structure usually found at the midline within abdominal segments two to four, but in gravid individuals the presence of eggs can displace it to other areas. The central structure is a transverse bar that supports three pairs of processes and one unpaired tooth; the inner anterior pair of processes are the longest, the lateral anterior pair are the smallest, and the lateral posterior pair are intermediate in size; a single dorsoventrally flattened tooth at the dorsal midline points anteriorly. Prehensor width range 0.32–0.41 mm, elytral width 4.0–5.5 times prehensor width. Females dissected, 12.

Life history. Little is known about the ecology and life history of S. goodrichi . Specimens have been taken at the type locality every month from May to August, all by UV light trap. In South Carolina, they were collected in May, July and September, at UV light and by sweeping near water, but no other collection or ecological data are provided. However, two well-known species in the genus, S. orbiculatus and S. tibialis , sympatric with each other and S. goodrichi , have aquatic larvae associated with decomposing plant material in marshes, ponds, springs, swamps, tree holes and phytotelmata ( Kraatz 1918; Beerbower 1943). The suggestion is strong therefore, that when studied, S. goodrichi will exhibit similar ecological and life history characteristics.

Figures

Figures 1–4. Scirtes goodrichi. 1) Adult dorsal habitus. 2) Female prehensor. 3) Mandible. 4) Prosternal process lateral aspect.

Figures 5–10. Scirtes goodrichi. 5) Male tegmen lateral view illustrating lateral lobe (paramere) and strut. 6) Male tegmen dorsal view illustrating lateral lobe (paramere) and strut. 7) Male penis, lateral view illustrating basal body (pala), median lobe (parameroid) and serrate process (trigonium). 8) Male penis, dorsal view illustrating basal body (pala), median lobe (parameroid) and serrate process (trigonium). 9) Male tergite VIII. 10) Male tergite IX. Scale lines = 0.1 mm.