Brachygluta (Brachygluta) dentata ( Say, 1824 )

Chandler, Donald S., Sabella, Giorgio & Bückle, Christoph, 2015, A revision of the Nearctic species of Brachygluta Thomson, 1859 (Coleoptera: Staphylinidae: Pselaphinae), Zootaxa 3928 (1), pp. 1-91 : 40-43

12. Brachygluta (Brachygluta) dentata ( Say, 1824)

( Figs 15 , 39 A)

Pselaphus dentata Say, 1824: 99 . Type locality: " United States "; types lost/destroyed, Neotype designated below. Two forms were described, one blackish, and one as a reddish-brown “var. a.”

Bryaxis dentata: Aubè 1844: 112 (as senior synonym for B. abdominalis ; indicates that the type is a female). LeConte 1849: 85; 1863: 21; 1880: 181 (key). Brendel 1865b: 256 (key); 1866a: 34; 1866b: 194 (female characters).

Bryaxis (Bryaxis) dentata: Brendel & Wickham 1890: 268 (key), 282 (redescription), plate IX, fig. 56. Casey 1894: 479.

Brachygluta dentata: Raffray 1904: 225 ; 1908: 231; 1911: 94. Leng 1920: 130. Bowman 1934: 83 (Group I, key), 84. Downie & Arnett 1996: 581. Poole & Gentili 1996: 380. Chandler 1997: 55. Peck & Thomas 1998: 39.

Material examined, 128 specimens. USA: Only continent on label: “Amerique” ( MNHN, 1M). District of Columbia: “D.C.” ( USNM, 4; MCZC, 6; MCZC, LeConte Collection, 3; SEMC, 2; ANSP, 3; DSCC, 1; CMNH, 11; FMNH, 1); Brend. ( MCZC, Horn Collection, 1). Wash.(ington), VI-20, Hubbard & Schwarz ( USNM, 1); M.L. Linell ( USNM, 1). Florida: Brevard Co.: Capron, IV-15 ( MCZC, LeConte Collection, Neotype). Titusville, III-21/ 22 -1939, F.E. Lutz ( AMNH, 6). Duval Co.: Pablo beach, IV-8, H.W. Wenzel ( FMNH, 1). St. Lucie Co.: Capron, IV- 22, Hubbard & Schwarz ( USNM, 1). Volusia Co. : Enterprise, V-19, Hubbard & Schwarz ( USNM, 1). Ormond, III- 17-1915 ( AMNH, 1); III-19-1915 ( AMNH, 1); [no date] ( AMNH, 3). Only state on label: “Fla” ( INHS, 4). Georgia: Laurens Co.: Dublin, VI-1960, light trap ( MHNG, 2). Richmond Co.: Brigan’s ( MNHN, 1M, 1F). Illinois: Only state on label: “Illinois”, V-13-1889 ( INHS, 1). Maryland: Baltimore Co.: Baltimore, VII-28, F.E. Blaisdell ( CASC, 1); VI-10, F.E. Blaisdell ( CASC, 1); VI-5-1966, E.J. Ford, light trap ( EJFC, 1). Calvert Co.: Kenwood Beach, 5 mi S Prince Frederick, IX-17-1950, G.H. Nelson, under wash-up log ( DSCC, 1). Plum Point, V- 28-1922 ( LSAM, 1). Somerset Co.: Somerset, VI-5-1971, E.J. Ford, Jr. ( DSCC 1). Marion, VII-13-1978 ( DSCC, 1). Crisfield, VIII-8-1956 (989I), R.D. Howard ( FMNH, 1); VIII-4-1932 ( LSAM, 1). St. Mary's Co.: Piney Point, Hubbard & Schwarz ( USNM, 1); VIII-26-1946, R.H. Beamer ( SEMC, 14). Only state on label: “Md.” ( CMNH, 3); Brend. ( MCZC, Horn Collection, 2). New Hampshire: Strafford Co.: Farmington, VIII-18-1896 ( MCZC, H.C. Fall Collection, 1). New Jersey: Ocean Co.: Long Beach, V-14-1961, E.J. Ford, Jr. ( DSCC 1). New York: Nassau Co.: Long Beach, L.(ong) I.(sland), VI-7-1925, Quirsfeld ( CNCI, 1); W. Beutenmuller ( MCZC, 1). Queens Co.: Rock(away) Beach, VI-11-1932, L.L. Buchanan ( LSAM, 1). Richmond Co.: S.I. (Staten Island) ( FMNH, 2). Only state on label: “N.Y.” ( CMNH, 1); Brend. ( MCZC, Horn Collection, 1). North Carolina: Macon Co.: Franklin, V- 8-1957, J.R. Vockeroth ( CNCI, 1). Mecklenburg Co.: Charlotte, V-11/17 -2005, J.F. Cornell, UV light trap ( LSAM, 1). Wake Co.: Raleigh, IV-12-1953, D.M. Weisman ( NCSU, 1); XII-5-1902, F. Sherman, Jr. ( NCSU, 1). Ohio: Only state on label: “Ohio” ( CMNH, 2). Pennsylvania: Philadelphia Co.: Frankford, V-20, G.M. Greene ( LSAM, 1). Only state on label: “Pen.” ( MCZC, LeConte Collection, 2). South Carolina: Aiken Co.: 1.3 mi N Jct. I-20 +US-1, XII-13/31 -1988, P. Skelly, pig dung and malt pitfall in sandhill scrub ( FSCA, 1). Charleston Co.: Charleston, 1945, O.L. Cartwright ( USNM, 1); IV-25-1945, R.L. Wenzel, light trap ( FMNH, 1). McClellansville, VI-1-1973, T. Daggy ( NCSU, 1). Texas: Only state on label: “Tx.”, through C. V. Riley ( USNM, 1). Virginia: Hampton City: Fort Monroe, IV-19, Hubbard & Schwarz ( USNM, 7); V-29 ( USNM, 4). King George Co.: Mathias Point, V-22- 1896 ( MCZC, H.C. Fall Collection, 1). Spotsylvania Co.: Fredricksburg, IV-29-1893, W.D. Richardson ( LSAM, 1); V-21-1891, W.D. Richardson ( USNM, 1); V-19-1991 ( MCZC, H.C. Fall Collection, 1). Virginia Beach: 1st Landing State Park, Chicken Turtle Pond, 36.9154, P.A. Bedel & A.C. Chazal, UV trap ( VMNH, 1). Virginia Beach, VII-17, Hubbard & Schwarz ( USNM, 1).

Description. BODY: Length 1.96–2.16 mm; orange-brown to elytra orange-brown and rest of body grading to brown; setae on head and pronotum short, curved and suberect, over rest of body setae appressed. Head: surface smooth, shining, punctures indistinct, setose area of median vertexal fovea as wide as to slightly smaller than those of lateral vertexal foveae. Antennomeres (both sexes) III–VI longer than wide, VII slightly longer than wide in male, as long as wide in female, VIII–X slightly wider than long ( Fig. 15 D). Pronotum: surface smooth, shining, punctures small, separated by two puncture diameters, setose area of median antebasal fovea about two-thirds width of setose areas of lateral antebasal foveae. Elytra: surface lightly microreticulate, punctures faint. Discal stria extending to about four-fifths of elytral length. Abdomen: tergite 1 with punctures of basal portion of disc sparse, surface shining, punctures becoming denser in apical half and surface appearing more opaque, particularly in area of male tergal projection. Basal striae of tergite 1 distinct, extending at most one-fourth length of paratergite; striae separated at base by about one-half tergal width, with sparse setal brush between striae, longer and more obvious in male.

MALE: Antennae not modified. Metaventrite with denser setae in triangular area from between metacoxae to middle. Tergite 1 protruding posteriorly to form median blunt angulation, in dorsal view tergite 1 covering other tergites ( Fig. 15 A); tergite 2 essentially vertical, transversely impressed at middle, setae dense at base in middle half; tergite 3 at middle with low oval tubercle densely setose at apex ( Fig. 15 B); in lateral view tergite 1 arcuate and protruding beyond tergite 2 ( Fig. 15 C). Trochanters not modified. Metatibiae narrow basally, slightly widening through length to apex, with dense comb of setae on mesal margin in apical fifth where slightly curved medially ( Fig. 15 E). Aedeagus 0.39 mm long; with dorsal plate triangular, apex bluntly pointed; parameres with three thick setae at posterior margin of preapical constriction, hyaline setae flattened, wide in apical half and then tapering to elongate acute point; internal sac with three large spines, two strongly curved ( Fig. 15 F).

FEMALE: Metaventrite with denser setae in triangular area from between metacoxae to near middle. Abdomen with all tergites evenly convex; ventrites broadly convex. Metatibiae similar to those of male.

Comments. The short original description by Say is not adequate for placement, and treats two apparent species: a smaller one whose tergum was "convex, simple, blackish," which indicates that a female was before him since females lack tergal modifications, while another specimen termed “var. a” was briefly described as "reddishbrown." LeConte’s (1851: 85) initial treatment of this species was vague, with Brendel (1865b) being the first to briefly but clearly place this species in a key. Brendel worked closely with LeConte and thanked him for all of assistance in his first paper ( Brendel 1865a), with this interpretation of the species continued in all subsequent papers by LeConte and Brendel.

Friedrich Ernst Melsheimer acquired and preserved many of the types of Thomas Say's species, which were then made available to LeConte as needed for his studies ( Hagen, 1884). LeConte (1875) reported that he had the opportunity to compare his specimens with many of those of Say, with these compared specimens residing in LeConte’s collection which is now held in the Museum of Comparative Zoology at Harvard University ( Hagen, 1884). In LeConte's series of this species the first specimen is a small dark female that bears the labels // [white circle] {LeConte color code = northern States, eastern states and Canada}/ ♀/ B. dentata (Say) Lec. //. This label is in LeConte's handwriting, and so removes this specimen from consideration as a Say type. The second, third, fourth, and eighth specimens are males of B. dentata in its current sense, which is based on a lighter brown species. It is informative that LeConte would place the dark specimen first in his series of B. dentata , with a series of lighter brown specimens following—paralleling the description of B. dentata and its “var. a” by Say. There are no specimens that can be placed as B. dentata in the remnants of the Say Collection at Harvard University, and no specimens of an appropriate age are recorded from the collections at The Natural History Museum, London, or are in the Museum d'Histoire naturelle in Paris. The Say types of this species are thought to be destroyed, and resolution of the placement of this species relies on selection of a neotype (see Mawdsley, 1993 for a discussion on selection of Say neotypes).

Say did not indicate a collection locality other than it was taken during the Major Long Expedition of 1819-- 1820 ( James, 1823) that started in Pittsburgh, Pennsylvania and proceeded to the eastern edge of the Rocky Mountains, and offered no explanation for the choice of the specific name “ dentata ,” which is an obvious feature of the male abdomen for this species in the sense of LeConte and Brendel. Careful examination of the dark first specimen in LeConte’s series reveals that it is a member of either B. arguta or B. wickhami , whose females cannot be placed to species. Both B. arguta and B. wickhami are species that typically occur in the Ohio River Valley and upper Mississippi River drainage. Brachygluta dentata in its current sense is more of an eastern coastal plain species, however, it historically was found in the Midwest and Southwest based on two specimens with an Ohio label, one with an Illinois label, and one with a Texas label examined during this study. While LeConte’s small dark specimen would be the best choice to serve as a neotype, it would lead to uncertainty in species identity, while the lighter brown and larger species in his series of B. dentata fits the very brief description of “var. a,” and is the species concept used in the papers of Brendel and LeConte starting in 1865. Due to the lack of resolution in species placement based on the dark form, LeConte's interpretation of this species is continued here by selection of a neotype from the major portion of his series for the following reasons: a) LeConte had access to the Say types via the Melsheimer Collection; b) there are two separate species present in LeConte's series of B. dentata that fit the limited descriptions of Say; c) the possibility that Say's reddish-brown specimen could be conspecific with B. dentata as currently defined due to a few specimens being labeled as being taken in Ohio and Illinois; and d) the males have tergite 1 with a conspicuous median “dentate” projection. A neotype is here selected from the J.L. LeConte Collection at Harvard University for Pselaphus dentata Say , which is the second in LeConte’s series and the first light brown specimen. It bears the labels: // ♂/ Capron 15.4 Fla/ 815/ dentata 2/ NEOTYPE Pselaphus dentatus Say des. DSChandler [yellow label]//. The next three specimens have the labels // D.C./ [male symbol]/ dentata 3 [4, and 8]//.

Collecting data. Few specimens have habitat or collecting data, but most of these were taken at ultraviolet lights, and one was found beneath a washed-up log on a beach and another was found in a dung pit-trap. Most specimens were collected from March to July, but a few collections were taken during the autumn and fall months, usually in Florida.

Distribution ( Fig. 39 A). This species is found in states bordering the Atlantic Coast, from New Hampshire to Florida, and occurs in the broader coastal plain as well as near and in the coastal marshes. However there are a few old specimens with state labels from Ohio, Illinois, and Texas that indicate a broader range than is demonstrated by more recented collected material. Leng (1920) records this species from Massachusetts, but no specimens from this state have been seen, though its occurrence there is expected.

Figures

FIGURE 15. Brachygluta dentata (Say). A: Abdomen, dorsal view. B: Abdomen, caudal view (South Carolina, Aiken Co.). C: Abdomen, lateral view (South Carolina, Aiken Co.). D: Right antenna (South Carolina, Aiken Co.). E: Left metatibia, anterior view (South Carolina, Aiken Co.). F: Aedeagus (Georgia, Laurens Co.).

FIGURE 39. Distribution map of Brachygluta dentata species-group. A: Brachygluta dentata (Say) (excluding Texas and Illinois, see text). B: Brachygluta lareaui Chandler. C: Brachygluta tamaulipec Sabella. (Red dot: material examined, green dot: only state on label).