Gnathymenus hoppi Bortoluzzi and Caron, 2018

Bortoluzzi, Sidnei & Caron, Edilson, 2018, A New Brazilian Species of Gnathymenus Solier (Coleoptera: Staphylinidae: Paederinae), The Coleopterists Bulletin 72 (1), pp. 166-170 : 166-169

Gnathymenus hoppi Bortoluzzi and Caron , new species

Zoobank.org/ urn:lsid:zoobank.org:act:E1126E41-A03F-4AE8-954D-B8406AE25846 ( Figs. 1–12 )

Type Material. Holotype: pinned, male ( Fig. 1 ), deposited in DZUP, with labels: 1) “ BRAZIL: PR [Paraná]: Res [Reserva]. Serra do Itaqui /APA Guaraquecaba Moist Lowland / Forest , sift. Litter , winkler extr./coll.: P. Hopp; 24.8-09-9.2007” [white label, printed in black]; 2) “ DZUP/268500 ” [white label, printed in black]; 3) “ Holotype / Gnathymenus hoppi / Bortoluzzi & Caron” [red label, printed in black]. Tewnty-nine paratypes with the same first label as holotype, the second label with number sequence from DZUP, detailed below,and third label as “ Paratype / Gnathymenus hoppi /Bortoluzzi & Caron” [yellow label, printed in black]. DZUP numbers 268499, 268502, 268492, 268486, 268491, 268493, 268495, 268496, 268497, 268498, 268501, 268503, 268504, 268512); five FMNH numbers 268468, 268470, 268471, 268472, 268473; five MZUSP numbers 268474, 268478, 268479, 268481, 268482; and five AMNH numbers 268484, 268485, 268487, 268589, 268490.

Diagnosis. Gnathymenus hoppi differs from other described species of Gnathymenus by aedeagal shape, which is slender and tapering toward the apex, somewhat S-shaped with apically beaked process, and with a small tooth on the subapical dorsal margin. This species does not fit into any of the groups named by Herman (1981).

Description. Body length 2.8–3.0 mm; pronotal width 0.4–0.5 mm. Body subcylindrical, elongated, and parallel-sided ( Fig. 1 ). Dorsal surface glossy. Color brownish. Dorsal integument of head and pronotum with sparse and moderately coarse punctation, dorsal surface of body covered with some long and sparse setae. Head: Transverse, approximately 1.1 times as wide as long, slightly widened behind eyes and with parallel sides; eyes small, not prominent, postocular area slightly longer than length of eyes. Labrum with U-shaped median emargination ( Fig. 3 ). Mandibles symmetrical, 2 teeth on inner margin of each ( Fig. 4 ). Labium with palpomere II longer than 3, long setae at apical margin ( Fig. 5 ); glossa split into 2 lobes. Gular 168 sutures separated, gular plate elongated ( Fig. 2 ). distinctly tapering posteriad. Prosternum transverse, Neck width 0.6 width of head. Thorax: Pronotum with short, triangular prosternal process. Scutellum strongly convex, 1.08 times as long as wide, slightly triangular and long. Elytra together shorter and more wider than head ( Fig. 1 ); widest in anterior half, slender than pronotum, slightly wider than long. Hind wings not developed (apterous). Abdomen: Slightly wider at segments VII–VIII, apical segment tapering. Segments III–VII with 2 pairs of paratergites, segments III–VI with paratergites parallel to each other, segment VII with paratergites separated in cross-section.

Male. Sterna III–VII with set of coarse setae near center ( Fig. 2 ); setae increasing in quantity and changing position from sternum III to VI, sternum III with fewer setae on posterior margin, sternum VI with many setae medially; coarse setae sternum VII sparser than on the preceding segment, but located more toward anterior margin ( Fig. 6 ); tergum VII with posterior margin truncate; sternum VII with posterior margin emarginated ( Fig. 6 ); tergum VIII with posterior margin projected, rounded at middle ( Fig. 7 ); sternum VIII with conspicuously narrow and deep median incision ( Fig. 8 ) that nearly reaches anterior margin of sternum; tergum IX with short ventral struts contiguous on anterior half ( Fig. 9 ); tergum X elongated and trapezoidal, barely extending beyond apex of tergum IX ( Fig. 9 ), anteriorly fused with tergum IX, but demarcated by an internal ridge; sternum IX elongated, anterior half submembranous, posterior half more sclerotized and pigmented; posterior margin truncate. Aedeagus very slender, tapering toward apex in ventral view; apical half somewhat S-shaped with apically beaked process and with a small tooth on subapical dorsal margin in lateral view ( Fig. 10 ); parameres small and short ( Fig. 10 , dashed line), with 2 apical setae on each.

Female. Sterna III–VII without set of coarse setae; tergum and sternum VII with posterior margin truncate; tergum VIII with posterior margin slightly projected; sternum VIII triangular, posterior margin rounded ( Fig. 11 ), with minute fringes on apex; tergum IX without ventral struts and contiguous on anterior third; tergum X oblong ( Fig. 12 , left arrow), extended beyond apex of tergum IX, anteriorly fused with tergum IX; extra ventral plate between sternum VIII and tergum IX ( Fig. 12 , right arrow), but the extra plate does not correspond to the same genital appendage mentioned for Gnathymenus species by Herman (1981). Spermatheca not found.

Distribution. The species is known only from the type locality in east Paraná, Guaraqueçaba, Serra do Itaqui, Brazil.

Etymology. This species name honors Dr. Philipp W. Hopp, the collector of the holotype.

Biological Notes. The specimens of G. hoppi were collected from sifted leaf litter in moist lowland forest by Winkler extracting technique.

Additional Notes. Gnathymenus hoppi is the 10 th species recorded in Brazil. According Newton and Caron (2017), the following species are recorded from Brazil: Gnathymenus bobelus Herman (Paraná) , Gnathymenus gomphus Herman (S~ ao Paulo), Gnathymenus klimai (Bernhauer) (Rio de Janeiro), Gnathymenus plancus Herman (Federal District and Paraná), Gnathymenus radulus Herman (S~ ao Paulo), Gnathymenus scoliodontus Herman (S~ ao Paulo and Santa Catarina), Gnathymenus setosus Herman (S~ ao Paulo), Gnathymenus umbus Herman (S~ ao Paulo), and Gnathymenus zarzus Herman (S~ ao Paulo).

Using Herman’ s (1981) key to Ganthymenus, G. hoppi keys to couplet 73. Below is a proposed modification of the key. The updated key does not include species described after 1981 from Ecuador by Assing (2013, 2015), Rougemont (2014), and Irmler (2015).

72(69). Right side of aedeagus with cylindrical, dorsolaterally directed process just distad of middle and flattened, laterally directed process at about apical quarter [see Herman 1981, figs. 457, 458]; Costa Rica............ .......................... Gnathymenus lirellus

- Aedeagus not as described and illustrated above ...................................... 73A

73A. Aedeagus long and slender, with short, hooked subapical process extending dorsally, strongly uncinated apically ( Fig. 10 ); Brazil............................................. ......... Gnathymenus hoppi , new species

- Aedeagus not as described above .... 73B

73B. Aedeagus, in lateral view, with short apical and longer subapical hooked processes [see Herman, fig. 189]; Colombia. .. .. .. .. ... .. .. .. .. Gnathymenus speccus

- Aedeagus gradually tapered to acute apex [see Herman 1981, figs. 141, 142]; Colombia........... Gnathymenus garus

Figures

Figs. 1–2. Gnathymenus hoppi. 1) Holotype, male, dorsal view; 2) Habitus, male, ventral view.

Figs. 3–12. Gnathymenus hoppi. 3) Labrum, dorsal view; 4) Mandibles, dorsal view; 5) Labium and mentum, ventral view; 6) Sternum VII, male, ventral view; 7) Tergum VIII, male, dorsal view; 8) Sternum VII, male, ventral view; 9) Terga IX+X, male, dorsal view; 10) Aedeagus, lateral view, paramere outlined by dashed line; 11) Sternum VII, female, ventral view; 12) Abdominal segments IX (right arrow) + X (left arrow), female.