Griburius scutellaris (Fabricius, 1801)

Sassi, Davide, 2023, Revision of the Griburius scutellaris (Fabricius, 1801) species group (Coleoptera: Chrysomelidae: Cryptocephalinae), Zootaxa 5315 (6), pp. 501-548 : 540-546

Griburius scutellaris (Fabricius, 1801)

( Figs 1a ; 11 ; 13f )

Cryptocephalus scutellaris Fabricius, 1801: 54 (original description); Olivier 1808: 807 (taxonomic notes).

Griburius scutellaris: Haldeman, 1849: 245 (taxonomic notes); Crotch, 1873a: 32 (taxonomic notes); Crotch, 1873b: 96 (catalogue); Clavareau, 1913: 91 (catalogue); Blackwelder, 1946: 640 (catalogue); Wilcox, 1954: 358 (catalogue); Pickle, 1971: 8 (taxonomic notes); Balsbaugh & Hays, 1972: 27 (catalogue and biological notes); Rouse & Medvedev, 1972: 78 (catalogue); Riley et al., 2003: 154 (catalogue); Clark et al., 2004: 139 (biological notes); Chamorro, 2013: 205 (taxonomic notes).

Scolochrus scutellaris: Suffrian, 1852: 128 (taxonomic notes).

Types. In ZMUC there was a single female, which matches the original description, even though it is devoid of informative labels. The certainty that ZMUC housed the well-preserved Fabricius collection drove me to consider this specimen as part of the type series and therefore the specimen has been designated as lectotype of the species. Since 2017 the entire Fabricius beetle collection was relocated to the Zoological Museum in Kiel, Germany (ZMK). LECTOTYPE: ♀, pinned, right elytron partly missing // “scutel laris” [white label, handwritten, barely readable] ( Fig. 11t ) // “ Griburius scutellaris Fabricius, 1801 ( Cryptocephalus scutellaris ) LECTOTYPUS D. Sassi det.” [red label, printed] // (ZMUC, now in ZMK).

Type locality. “ Carolina ” ( U.S. A) .

Additional material examined. U.S.A.: ALABAMA: Mobile Co.: Mobile (6, FIMU & ZMUC) . ARKANSAS: Craighead Co.: Jonesboro 29.VII.2022 (1, GBIF) . Faulkner Co.: Conway 22.V.2020 (1, GBIF) . Garland Co.: Camp Clearfork Hwy 270 20 mi E Hot Springs 14.VI.1997 (1, TAMU) ; Newton Co.: Pritt 21.V.1995 (2, BYU) . FLORIDA: Bay Co.: Callaway 7.V.1974 (1, BYU) . GEORGIA: Bartow Co.: Atlanta env. Allatoona Lake Kocian (2, NMV) ; “ Georgia ” (3, MLUH) . ILLINOIS: Jefferson Co.: Mount Vernon 18.VI.1993 (1, BYU) . INDIANA: Brown Co.: (3, FIMU) ; Parke Co.: (3, FIMU) ; Tippecanoe Co.: (18, FIMU) . KANSAS: Douglas Co.: Lawrence Prairie Park 19.VI.2022 (1, GBIF) . Pottawatomie Co.: 6 mi E Tuttle Creek Dam 2.VI.1987 (2, ERPC) . LOUISIANA: Bossier Par. : Bodcau Wldf. Mgt. Ar. nr Rifle Range 20.V.1996 (2, TAMU) ; East Baton Rouge Par.: Baton Rouge 25.IV.1982 & 6.V.1982 & 26.IV.1986 & 10.V.1987 (7, MSNG) ; Baton Rouge place DuPlantier Apts. 30.V.1983 (1, ERPC) ; East Feliciana Par. : 5.6 mi N Slaughter 26.IV.1981 (1, ERPC) ; Iberville Par.: Whiskey Bay 8.V.2010 (1, BYU) ; Natchitoches Par.: Kisat. nat. For. Red Dirt W.M.A. 27.IV.1985 (3, ERPC) ; Rapides Par.: Woodworth 21.IV.2022 (1, GBIF) ; Tangipahoa Par. : 4 mi N Robert 25.IV.1981 (9, ERPC) . MISSOURI: “ Missouri ” (1, FIMU) ; Barry Co.: Roaring River St. Pk 8.VI.1979 (3, ERPC) ; Callaway Co.: Tucker Prairie 7.VI.1978 (1, ERPC) ; Carter Co.: Skyline Drive nr Van Buren 22.VII.1978 (1, ERPC) ; Greene Co.: nr James R. 15.VI.1929 (1, TAMU) ; Hickory Co.: Pomme de Terre 1.VI.1979 (2, TAMU) ; Iron Co.: Taum Sauk S.P. igneous glade 15.V.2000 (1, TAMU) ; Jackson Co.: Jackson Co. VI.1953 (1 TAMU) . Jefferson Co.: De Soto 14.V.2021 (1, GBIF) . Lawrence Co.: Mount Vernon Pra. 8.VI.1980 (1, ERPC) ; Randolph Co.: 1 mi E Moberly V.1973 & VI.1973 (15, MSNG) ; St. Clair Co.: Lichen Glade 6 mi W Osceola 12.VI.1978 (2, BYU & ERPC) ; St. Francois Co.: St. Francois St. Pk. 21: VI.1978 (2, ERPC) ; Wiggins Miss. [maybe Wiggins Hill in St. Francois Co.] 5.V.1931 (4, TAMU) ; Stoddard Co.: 2.8 mi NE Dexter Holly Preserve (1, ERPC) ; Wayne Co.: 3 mi W Waynesville 23.VI.1978 (1, ERPC) . NEW YORK: Westchester Co.: Yonkers 2.IX.1929 (1, FIMU) . NORTH CAROLINA : Brunswick Co.: 2.7 mi N Ocean Isle Beach 14.VI.2013 (2, BYU) ; Mecklenburg Co.: Charlotte Beverly Woods 5.VI.1964 (1, MSPC) ; Orange Co.: Chapel Hill 9.VI.2022 (1, GBIF) ; Wake Co.: Raleigh 25.V.1971 (2, MSPC) . OHIO: Clinton Co.: 15.VI.1962 (1, BYU) ; Fairfield Co.: Barnebey Center 11.V.1985 (1, BYU) . OKLAHOMA: Latimer Co.: Latimer Co. V.1985 & V.1986 & V.1983 & VI.1983 & V.1982 & V.1990 & V.1988 & V.1993 (16, TAMU) ; 5 mi E Red Oak V.1981 (1, TAMU) . PENNSYLVANIA: Philadelphia Co.: Houston Meadow, Fairmount Park Philadelphia 4.VI.2016 (1, GBIF) . SOUTH CAROLINA : Berkeley Co.: Pinopolis 28.V.2006 (2, BYU) ; Francis Marion National Forest Dog Swamp 28.V.2006 (1, BYU) ; Charleston Co.: Meggett Roxbury Park 18.V.2014 (1, GBIF) ; Oconee Co.: Mountain Rest 23.VI.1951 (1, TAMU) ; Sumter Co.: Manchester State Forest 5.5 mi N Rimini 29.V.2006 (1, ERPC) . TENNESSEE: Rutherford Co.: Flat Rock Cedar Glade and Barrens State Natural Area 4.VI.2014 (1, BYU) . TEXAS: “ Texas ” (2, NHMP & MNHUB) ; Anderson Co.: Salmon 28.IV.1975 & 7.VI.1995 & 28. IV.1975 Malaise trap 4, TAMU); Bastrop Co. : Bastrop St. Pk. 10.V:1992 (1, MSNG) ; Bastrop State Park 10.V.1989 (21, TAMU) ; Bastrop State Park 19.IV.1990 (2, ERPC) ; 1.5 mi W jct Hwy 21 Hwy 290 15.IV.2007 (4, ERPC) ; Bastrop 29.V.1997 (1, TAMU) ; Hwy 21 2 mi NE Bastrop 3.V.1999 (1, BYU) ; 2–5 mi E jct Hwy 95 on Hwy 21 10.V.1992 & 28.V.1992 (4, ERPC & TAMU) ; Brazos Co.: College Station 7.IX.1930 & 27.IV.1935 & 16.IV.1978 (3, TAMU) ; Burleson Co.: Big Creek Park Lake Somerville 16.III.1971 (1, TAMU) ; L. Somerville edge 11.IV.1982 (1, TAMU) ; Erath Co.: Bluff Dale 1 mi N Paluxy River 19.V.1978 Malaise trap (1, TAMU) ; Freestone Co.: Old Spring Seat Church nr Donie 6.V.1995 (1, TAMU) ; Gonzales Co.: 0.5 mi E jct. 304 1.IV.1983 (1, ERPC) . Jackson Co.: 5 mi S Eona on Oak 18.IV.1974 (1, FIMU) ; Tyler Co.: Kirby State Forest 26.V.2007 (4, BYU & ERPC) ; Victoria Co.: 9 mi NE Victoria 17.V.1979 (1, ERPC) ; 3 mi S Inez 6.V.1978 (1, FIMU) . VIRGINIA: Fairfax Co.: Chantilly 12.VI.2009 (1, WGPC) . WEST VIRGINIA: Braxton Co.: Burnsville Lake W.M.A. Little Kanawha River at TylerRun 2.VI.1999 (3, BYU) ; Jackson Co.: Frozencamp Wildlife Management Area 21.V.1998 (1, BYU) ; Kanawha Co.: Rocky Shoal Creek N of Pocalitico River 9.VI.2012 (2, BYU) ; Mason Co.: McClintic Wildlife Management Area 5.VI.1996 (2, BYU) ; Chief Cornstalk Wildlife Management Area 8.VI.2000 (1, BYU) .

Additional data from literature. Oklahoma ( Pickle, 1971); Arizona ( Balsbaugh & Hays, 1972); Arkansas ( Rouse & Medvedev, 1972); Ohio ( Wilcox, 1954). Riley et al. (2003) also report Maryland, without more precise indication, as part of the species’ range. I did not see any specimens from that state.

Distribution. U.S.A.: Alabama, Arkansas, Florida, Georgia, Illinois, Indiana, Louisiana, Maryland, Missouri, New York, North Carolina , Ohio, Oklahoma, South Carolina , Tennessee, West Virginia.

Diagnosis. Darker specimens are usually well distinguished from the other species, while the lighter ones can sometimes be similar to Griburius larvatus and G. rileyi . However, in G. scutellaris the pronotal black pattern is usually more extended and differently arranged. Moreover, the pygidium is never completely yellow as observed in G. larvatus and G. rileyi . The aedeagal median lobe is almost devoid of ventral carina and more flattened in lateral view than in G. larvatus , while in G. rileyi the apical denticle is smaller and shorter.

Description of male. BL = 3.8–4.3 mm, BW = 2.4–2.8 mm, PL = 1.3–1.7 mm, PW = 2.0– 2.4 mm. Interocular distance 7.0–7.9 % of BL.

Head ( Fig. 11d ) yellow, usually with vertex, lower rim of clypeus, insertion of antennae and square patch between upper ocular lobes black. Labrum yellow. Vertex bright, sparsely and shallowly punctured with very short, recumbent, whitish setae. Surface of frontoclypeal area bright as well, with irregularly scattered punctation, coarser on yellow areas, and sparse short setae. Mid-cranial suture well detectable on vertex and between upper lobes of eyes. Upper lobes of eyes well separated from each other along midline. Ocular lines very weakly impressed, barely discernible. Ocular canthus large not differentiated in punctation and setosity from the remainder of frontoclypeal surface. Antennae ( Fig. 11s ) rather short with antennomeres 3–5 yellow, bright, subcylindrical; antennomeres 6–11 brownish, dull, more flattened and more diffusedly setose.

Pronotum black with yellow stripes along lateral margins, fairly broadened at anterior angles and often extended to outer third of anterior margin. At times short longitudinal median stripe on anterior half of disc, not reaching anterior margin. Pronotal shape roughly elliptical, scarcely transverse, usually quite regularly convex on disc, at times slightly flattened. Lateral margins narrow, not visible from above, regularly curved so that maximum width nearly at middle. Surface moderately shiny usually with scattered, fine punctation at middle of disc. Punctures coarser and more deeply impressed along sides and in proximity of posterolateral impressions. Sometimes punctation on central part of disc almost as strong as across lateral area. Posterolateral impressions well impressed and obliquely arranged, marked at bottom of depression by some strong punctures. Pronotal posterior margin thickened along posterolateral impressions.

Scutellum yellow, subtriangular with apex shortly truncated. Surface minutely and sparsely punctured, with few, very short setae.

Elytron black with mildly twisting, transverse yellow band at middle, starting from lateral margin but not reaching suture. Such band extending along margin up to anterior angle. Further rounded yellow spot at elytral apex. Sometimes additional small yellow patch beside scutellum. Yellow elytral pattern often much more developed, with dark colour reduced to series of rounded spots: one on humeral callus, a second one along basal margin just beside scutellum, third one just behind midline, further one (or two) along suture. Such spots sometimes partly fused together. In lighter colored specimens elytron totally yellow or with single rounded spot on humeral callus. Epipleuron light yellow. Elytral outline short with sides almost straight and weakly convergent posteriorly. Lateral margins narrow, simultaneously visible from above only along posterior half. Elytral surface slightly flattened on disc, moderately shiny, with strong punctation arranged in almost regular rows, distinct up to posterior clivus. Intervals flat. Postscutellar area fairly raised. Humeral callus prominent, impunctate. Epipleuron smooth, impunctate, with convex surface.

Pygidium ( Fig. 11e ) yellow with black patch at apex, more or less extended medially toward base. Surface bright, covered with close shallow punctures and appressed, pale setae.

Ventral parts of thorax totally black. Abdominal ventrites black with yellow sides. Hypomera, mesepimera and mesepisterna almost bare, shiny, with coarse, well-impressed, scattered punctures. Remainder of ventral surface of thorax rather shiny as well, covered with fine punctures and regularly distributed, sparse, whitish setae. Prosternal process large, with sides almost straight between anterior coxae, then converging in large, round apex; surface feebly depressed at center, covered with coarse, shallow punctures and sparse, long, semi-erect setae. Legs yellow, sometimes tarsi slightly darkened.

Median depression on fifth abdominal ventrite very shallow and hardly detectable, but with fewer setae and punctures than remainder of ventrite surface. Ventrite posterior margin very slightly notched. Median lobe of aedeagus ( Fig. 11m –p ) with apex rather long, blunt, triangular. Ventral outline slightly convex but devoid of true carina. Setose depressions shallow, weakly delimited, with surface covered with very small punctures and arcuate setae.

Female. Habitus in Fig. 11a–b (LT). BL = 4.8–5.9 mm, BW = 3.1–3.4 mm, PL = 1.7–1.9 mm, PW = 2.7–3.0 mm. Interocular distance 11.9–12.5 % of BL.

Females are larger with eyes ( Fig. 11c ) smaller and more separated along midline. The head is black with yellow “eyebrows” along the upper margin of eyes. Besides, a transverse winding ribbon-like yellow band between ocular canthi is almost often detectable. Yellow pattern on pronotum is at times more extended, this can be observed in males as well, but it seems to be more frequent in female. Additionally, abdominal ventrites 2–3 are often totally black.

The fifth abdominal ventrite in females has a large, rounded and deep pit. The bottom of the pit is brownish (while the remainder of the ventrite is yellow), glabrous, matt, impunctate but covered by tiny wrinkles. The vasculum of the spermatheca ( Fig. 11q ) is scarcely pigmented, sickle-shaped with rather long, fairly swollen proximal lobe. The distal lobe is short, slender, tapered with a rather acute apex mildly bent downwards. The ampulla is not pigmented, lengthened, slightly curled. The insertion on the bursa copulatrix is simple, short and not pigmented. The sperm gland insertion is longer, slightly tapered distally and bent upwards. The duct is uniform in size, slender, quite rigid, not coiled but with a series of 4–6 turns close to the vasculum. The insertion on the bursa copulatrix is simple, but partially surrounded by an arcuate and pigmented thickening of the membrane.

Remarks. The chromatic pattern in this species tends to vary according to a rather evident geographic gradient. In fact, specimens from Northern and Eastern part of the range show a darker colouration, while across the southwestern regions (i.e., Texas, Oklahoma and Louisiana) the dorsal black pattern, both on the pronotum and on the elytra, is on the whole variously reduced. However, single specimens not fitting the gradient are present even at the opposite ends of the range.

Figures

FIGURE 1. Median lobe of aedeagus with everted endophallus. a: G. scutellaris, lateral view (Wiggins, Missouri); b: G. albilabris, lateral view (Nayarit, Mexico); c: G. decoratus, lateral view (Melinda, Belize); d: G. larvatus, lateral view (Big Pine Key, Florida); e: G. larvatus, dorsal view (Big Pine Key, Florida). as: anterior sclerite; ps: posterior sclerite; ds: dorsal side of median lobe. Dissections and photos thanks to the courtesy of M. Bollino (Lecce).

FIGURE 11. G. scutellaris. a–b: habitus, dorsal and lateral view (LT); c: frontal view, female (LT); d: frontal view, male (Red Dirt National Wildlife Management Area, Louisiana); e: posterior view, female (Somerville Lake, Texas); f–k: colour variations (f: male, Allatoona Lake, Georgia; g: female, Somerville Lake, Texas; h–k: males, Red Dirt National Wildlife Management Area, Louisiana); m–p: median lobe of aedeagus in ventral (m), dorsal (n) and lateral (p) view [0.6 mm]; s: antenna [0.9 mm]; q: spermatheca [0.4 mm]; t: original label of the LT. hd: setose depressions. Square brackets: length of scale segment.

FIGURE 13. Distribution maps for the Griburius scutellaris species-group. a: G. lecontii, Mexican range; b: G. lecontii, U. S. range; c: G. montezuma, Mexican and Central American range; d: G. montezuma, U. S. range; e: G. rileyi; f: G. scutellaris. Black markings: data from specimens analyzed during the study. Red markings: data from the public database Global Biodiversity Information Facility (GBIF.com) or literature data. Black stars: the presence in the state is reported in the consulted literature, but without more precise data on the location.