Tachytes gyusanus, Back, Yeong-Bin & Kim, Jeong-Kyu, 2014

Back, Yeong-Bin & Kim, Jeong-Kyu, 2014, Review of the genus Tachytes Panzer (Hymenoptera: Crabronidae: Crabroninae) of South Korea, with description of one new species, Zootaxa 3795 (3), pp. 301-310 : 304-307

Tachytes gyusanus sp. n.

Diagnosis. Vestiture on head and mesosoma golden; metasomal terga I–IV with pale yellow (tergum I) to silvery white (terga II–IV) apical setal band that are broad, about three to four × MOD. LID somewhat broad, ca. 1.5 × as long as flagellomere I ( Fig. 2 I and J; Fig. 3 A). Propodeal dorsum without median longitudinal furrow or at most with a very short evanescent furrow basally; median longitudinal linear part with dense appressed setae ( Fig. 3 B). Description. Female. Body length 13.5–15.0 mm ( Fig. 1 E and F).

Head. MID ca. 3.2 × as long as LID ( Fig. 2 I). Upper frons and vertex with both small and medium-sized punctures irregularly and densely set. Ocellar scar ca. 3.0 × as long as MOD; lower tip of ocellar scar separated from midocellus by ca. 2.0 × MOD. Clypeus ca. 2.4 × as long as broad, its apical margin between sublateral teeth broadly rounded or somewhat straight (between median notch and sublateral tooth) and slightly notched medially ( Fig. 2 E), with dense medium-sized punctures regularly set. Flagellomere I ca. 2.5 × as long as broad, almost as long as flagellum II; apical flagellomere ca. 4.2 × as long as broad, almost as long as penultimate one. Frons below ocellar scar and clypeus with both dense appressed and sparser erect long golden setae ( Fig. 2 J).

Mesosoma. In addition to setal condition described in key, mesopleuron, propodeal dorsum and propodeal lateral face with dense erect golden setae. Mesopleuron, mesoscutum, scutellum, metanotum and propodeal lateral face with dense medium-sized punctures regularly set. Propodeal impression almost an isosceles triangle in shape, and ca. 2.0 × as long as broad. Propodeal dorsum weakly reticulate.

Metasoma. Lateral parts of terga II–III, lateral parts and dorsum of terga IV–V, apical parts of sterna II–V and lateral parts of sternum VI with long sparse brownish bristles. Terga I–V and sterna II–III with small punctures moderately (separating one another by puncture diameter or a little more) and regularly set; sterna IV–V with small to medium-sized punctures moderately and irregularly set; sternum VI with both sparse medium-sized and large punctures irregularly set. Pygidial plate almost an equilateral triangle in shape with apical margin shortly truncate ( Fig. 3 C).

Coloration. Ground color black, following parts brown to reddish brown: basal half of mandible, palpi, tegula, apical half or slightly less of all femur, all tibiae, all trochanters and spurs and spines of all legs.

Male. As in female, but different in following details. Body smaller, 12.3–14.3 mm long. MID ca. 2.9 × as long as LID ( Fig. 2 J). Bristles on pygidial plate pale golden.

Genitalia. As in Fig. 4 H (dorsal view) and Fig. 4 I (lateral view): gonocoxite broad and tapering, without distinct tubercle in its proximal part; middle constriction of aedeagus inconspicuous.

Type-specimens. Holotype. female, pinned. Original label: “Daegok-ri, Haemi-myeon, Seosan-si, Chungcheongnam-do, 4.viii.2011, Y.B. Back” [white printed label], “ HOLOTYPE / Tachytes / gyusanus / Back et Kim / sp. n. / 2014” [red handwritten label]. Paratypes (all are pinned and have both white printed labels of locality and collector and red handwritten labels of designation of PARATYPE). 4 ♀, 3 ♂, Sannae-ri, Moga-myeon, Icheon-si, Gyeonggi-do, 18.viii.2011 (J.K. Kim); 2 ♀, ditto, 12.viii.2010 (Y.B. Back); 1 ♂, Boche-ri, Miyangmyeon, Anseong-si, Gyeonggi-do, collect date and collector not stated; 5 ♂, Daegok-ri, Haemi-myeon, Seosan-si, Chungcheongnam-do, 4.viii.2011 (Y.B. Back); 1 ♂, Mt. Suri, Sokdal-dong, Gunpo-si, Gyeonggi-do, 29.vii.2008 (J.K. Kim); 2 ♀, ditto, 4.viii.2011 (Y.B. Back); 2 ♂, Is. Guleop, Guleop-ri, Deokjeok-myeon, Ongjin-gun, Incheon Metropolitan City, 12.viii.2010 (Y.B. Back); 1 ♀, ditto, 30.vii.2004 (D.S. Choi); 1 ♂, Nocheon-ri, Dong-myeon, Hongcheon-gun, Gangwon-do, 27.vii.2010 (E.Y. Jung); 1 ♀, ditto, 20.viii.2001 (H.S. Lee); 1 ♀, Daeryul-ri, Daeheung-myeon, Yesan-gun, Chungcheongnam-do, 9.ix.2007 (S.B. Ha); 1 ♂, Munchon-ri, Gamgok-myeon, Eumseong-gun, Chungcheongbuk-do, 8.viii.2006 (S.P. Han); 1 ♀, Waryong-dong, Sacheon-si, Gyeongsangnam-do, 21.viii.2001 (J.H. Son); 1 ♀, 1 ♂, Yonsei Univ. Wonju Campus, Maeji-ri, Heungeop-myeon, Wonju-si, Gangwondo, 25.vii.1996 (H.W. Byun).

Etymology. Specific name is given in memory of the late Dr. C.W. Kim who was a founder entomologist of Hymenoptera taxonomy in Korea. GYUSAN is his added name.

Distribution. South Korea.

Remarks. This new species superficially resembles Tachytes modestus in setal condition and coloration ( Fig. 1 D and E). However, in addition to several distinctive characteristics given in the key, male genital structure is critically different: in the new species, the distal triangular part of the aedeagus is longer in dorsal view, and the gonocoxite is broad and evenly tapering, without proximal tubercle; the corresponding part of the aedeagus is shorter and the gonocoxite is narrower and rod-shaped, with a triangular proximal tubercle in T. modestus . Setal condition of the propodeal dorsum is unique in the new species. The median longitudinal part of the propodeal dorsum is covered with dense appressed setae in the new species ( Fig. 3 B), whereas the narrow median longitudinal linear area (i.e., shallow longitudinal furrow) is almost bare in the other Korean species ( Fig. 3 E).

This new species was very often observed on flowers of Zanthoxylum schinifolium S. et Z. ( Rutaceae ) during late June to early September.

Figures

FIGURE 1. Female habitus of Korean Tachytes species. A, T. sinensis. B, T. etruscus sibiricus. C, T. fruticis. D, T. modestus. E, T. gyusanus n. sp., in dorsal view. F, T. gyusanus n. sp., in profile. Scale bars: 1 mm.

FIGURE 2. Head in full frontal views and clypeal apical margin (bottom line drawing of each image) of Korean Tachytes species. A, T. sinensis, female. B, T. sinensis, male. C, T. etruscus sibiricus, female. D, T. etruscus sibiricus, male. E, T. fruticis, female. F, T. fruticis, male. G, T. modestus, female. H, T. modestus, male. I, T. gyusanus n. sp., female. J, T. gyusanus n. sp., male.

FIGURE 3. Selected characteristics of T. gyusanus n. sp. and T. modestus. A-C, T. gyusanus n. sp.: A, head, in dorsal view, showing broader LID; B, propodeal dorsum with dense appressed setae in median part; C, pygidial plate. D-F, T. modestus: D, head, in dorsal view, showing narrower LID; B, propodeal dorsum with shallow median longitudinal furrow, but without dense appressed setae in median part; C, pygidial plate.

FIGURE 4. Male genitalia and sternum VIII. A, genitalia of T. sinensis, in dorsal view. B, sternum VIII of T. sinensis. C, sternum VIII of T. etruscus sibiricus. D, genitalia of T. etruscus sibiricus, in dorsal view. E, sternum VIII of T. fruticis. F, genitalia of T. fruticis, in dorsal view. G, genitalia and sternum VIII of T. modestus, in dorsal view. H, genitalia of T. gyusanus n. sp., in dorsal view. I, genitalia of T. gyusanus n. sp., in lateral view. J, sternum VIII of T. gyusanus n. sp.