Dolichomitus Smith, 1877

Sheng, Mao-Ling, Lü, Jun, Liao, Cheng-Jia, Li, Tao & Sun, Shu-Ping, 2022, Two species of Dolichomitus Smith, 1877 (Hymenoptera, Ichneumonidae, Pimplinae) parasitizing borers of Juglans mandshurica Maxim. and a key to species known from China, European Journal of Taxonomy 839, pp. 1-13 : 3-5

Genus Dolichomitus Smith, 1877

Dolichomitus Smith, 1877: 411 .

Type species

Dolichomitus longicauda Smith, 1877 .

Diagnosis

The diagnosis of the genus was modified from Townes (1969) and Sheng & Sun (2010).

Apical portion of clypeus impressed, apical margin always with deep median notch ( Fig. 2 ). Occipital carina complete, strongly dipped dorsomedially. Fore wing vein M&RS usually opposite 1cu-a; areolet present, large. Hind wing vein 1-cu shorter than cu-a. Tarsal claws of female with large basal lobe. Lateromedian longitudinal carinae of propodeum nearly always more or less present anteriorly. Anterior two tergites almost equal length. Tergite 2 with anterolateral oblique grooves cutting off triangular areas, these grooves more longitudinal than transverse. Tergites 3 and 4 nearly always with distinct lateral swellings. Subapical portion of ovipositor partially subtended by distinct dorsal lobe of lower valve, lobe always with distinct ridges.

Key to the species and subspecies of Dolichomitus Smith, 1877 known from China (females only)

1. Dorsal lobe of lower valve of ovipositor with 2 ridges, which are strongly convergent dorsally .... 2

– Dorsal lobe of lower valve of ovipositor with at least 3 ridges, which are not convergent dorsally 4

2. Tergites 2 and 3 with distinct dense punctures, without transverse wrinkles. Tergite 3 1.0–1.35 × as long as posterior width. Ovipositor sheath slightly longer than body. Base of lateromedian longitudinal carinae of propodeum weak ...................................................... D. pterelas (Say, 1829)

– Tergites 2 and 3 with distinct fine transverse wrinkles, partly with fine punctures. Tergite 3 1.5– 1.75 × as long as posterior width. Ovipositor sheath at least 1.5 × as long as body. Lateromedian longitudinal carinae of propodeum distinct ...................................................................................... 3

3. Middle coxa 2.6 × as long as maximum width. Hind coxa 2.0 × as long as maximum width. Tergite 3 partly with distinct fine punctures. Pterostigma yellow brown. Hind coxa black. Dorsal profile of hind femur brownish black ............................................................... D. matsumurai ( Uchida, 1928)

– Middle coxa 2.0 × as long as maximum width. Hind coxa 2.5 × as long as maximum width. Tergite 3 with indistinct fine punctures. Pterostigma blackish brown. Hind coxa red. Hind femur red brown ......................................................................................... D. imperator (Kriechbaumer, 1854)

4. Ovipositor sheath at least 2.5 × as long as body ............................................................................... 5

– Ovipositor sheath not more than 2.0 × as long as body .................................................................... 8

5 Mandible unspecialized, not bent medially. Dorsal lobe of lower valve of ovipositor with 6–7 ridges. Coxae red to reddish brown .............................................................................................................. 6

– Mandible strongly bent medially inward almost at right angle. Dorsal lobe of lower valve of ovipositor with 5 ridges. Coxae black .............................................................................................. 7

6. Frons with fine punctures. Lateromedian longitudinal carinae of propodeum absent. Tergites indistinctly punctate. Tergite 2 about as long as posterior width. Ovipositor sheath at least 3.5 × as long as body. Basal 3 ridges of dorsal lobe of lower valve of ovipositor strongly reclivous. Apical portion of hind tibia brownish black. Hind tarsus black ................. D. cephalotes (Holmgren, 1860)

– Frons with fine transverse aciculations. Anterior 0.4 of lateromedian longitudinal carinae of propodeum present. Tergites with dense coarse punctures. Tergite 2 longer than posterior width. Ovipositor sheath at most 3.0 × as long as body. Basal ridges of dorsal lobe of lower valve of ovipositor distinctly arched backward. Hind tibia and tarsus red brown .. D. atratus (Rudow, 1881)

7. Median portion of tergite 1 rugulose, antero-median portion between latero-median carinae with fine transverse wrinkles. Fore femur entirely yellow brown ............. D. khasianus Gupta & Tikar, 1976

– Tergite 1 irregularly rugulopunctate, without transverse wrinkles. Posterior profile of fore femur with distinct longitudinal black spot ................................................... D. flavicrus Matsumoto, 2018

8. Dorsal lobe of lower valve of ovipositor with at least 5 ridges ........................................................ 9

– Dorsal lobe of lower valve of ovipositor with 3–4 ridges .............................................................. 14

9. Lower half of mesepisternum with dense setae. Ovipositor sheath all most 2.0 × as long as fore wing [Median flagellomeres of male strongly expanded and white ventrally]. D. sericeus (Hartig, 1847)

– Mesepisternum with sparse fine setae. Ovipositor sheath not more than 1.7 × as long as fore wing ................................................................................................................................................ 10

10. Tergite 2 1.7 × as long as posterior width. Tergite 3 1.4 × as long as posterior width. Dorsal lobe of lower valve of ovipositor with 6 ridges ............................................... D. songxianicus Sheng, 2004

– Tergite 2 1.0–1.5 × posterior width. Tergite 3 quadrate or slightly longer than posterior width .....11

11. Upper end of epicnemial carina reaching front edge of mesopleuron. Pterostigma blackish brown. Dorsal lobe of lower valve of ovipositor with 6 ridges ...................................................................... .................................................................................. D. tuberculatus tuberculatus (Geoffroy, 1785)

– Upper end of epicnemial carina not reaching front edge of mesopleuron. Pterostigma yellow brown .............................................................................................................................................. 12

12. Ridges of dorsal lobe of lower valve of ovipositor densely evenly arranged, strongly inclivous ...... ......................................................................................................... D. populneus (Ratzeburg, 1848)

– Ridges of dorsal lobe of lower valve of ovipositor not evenly arranged, at least basal ridges vertical ............................................................................................................................................ 13

13. Fore wing vein M&RS opposite 1cu-a. Hind wing vein 1-cu distinctly shorter than cu-a. Tergites 2 and 3 each about as long as posterior width. Basal ridges of dorsal lobe of lower valve of ovipositor vertical. Hind tibia red brown ............................................... D. messor messor (Gravenhorst, 1829)

– Fore wing vein M&RS slightly postfurcal. Hind wing vein 1-cu almost as long as cu-a. Tergites 2 and 3 transverse. All ridges of dorsal lobe of lower valve of ovipositor vertical. Basal portion of hind tibia yellow, apical brownish black ........................................................ D. brevissimus Sheng, 2009

14. Dorsal lobe of lower valve of ovipositor with 3 ridges .................................................................. 15

– Dorsal lobe of lower valve of ovipositor with 4 ridges .................................................................. 17

15. Hind wing vein 1-cu slightly shorter than cu-a. Tubercles of tergites 3–5 indistinct. Ovipositor sheath 4.7 × as long as hind tibia ............................................................................... D. debilis Sheng, 2002

– Hind wing vein 1-cu approximately 0.3 × as long as cu-a. Tergites 3–5 with distinct tubercles. Ovipositor sheath more than 5.0 × as long as hind tibia ................................................................. 16

16. Malar space 0.4 × as long as basal width of mandible. Postocellar line 0.5 × as long as ocular-ocellar line. Mesopleuron with sparse punctures. Hind coxa black ................... D. triangustus Wang, 1997

– Malar space 0.2 × as long as basal width of mandible. Postocellar line 0.8 × as long as ocular-ocellar line. Mesopleuron with dense punctures. Hind coxa red brown ................. D. jiyuanensis Lin, 2005

17. Lateromedian longitudinal carinae of propodeum strongly divergent posteriorly. Tergite 2 quadrate. Maxillary and labial palpi dark brown. Tegula yellow, posterior margin blackish brown. Apical portion of hind femur black. Hind coxa red .................................... D. diversicostae (Perkins, 1943)

– Lateromedian longitudinal carinae of propodeum parallel, or absent. Other characters not entirely as above, tergite 2 usually longer than posterior width, maxillary and labial palpi yellow or reddish brown, or tegula dark, or hind coxa black ...................................................................................... 18

18. Tergites 3–4 elongate, distinctly longer than posterior width ......................................................... 19

– Tergites 3–4 almost quadrate, or transverse .................................................................................... 21

19. Mandible strongly bent medially almost at right angle. Face with dense white setae. Lateromedian longitudinal carinae of propodeum distinctly present anteriorly. Fore and middle legs reddish to yellowish brown .............................................................................. D. mandibularis (Uchida, 1932)

– Mandible normal, not strongly bent medially. Face without dense white setae. Other characters not entirely as above ............................................................................................................................. 20

20. Lateromedian longitudinal carinae of propodeum present anteriorly. Hind coxa, trochanter and femur red to reddish brown ...................................................... D. mesocentrus (Gravenhorst, 1829)

– Lateromedian longitudinal carinae of propodeum absent. Hind leg entirely black ............................ ................................................................................. D. melanomerus tinctipennis (Cameron, 1899)

21. Mesopleuron smooth except anterior margin finely punctate. Fore and middle coxae yellow ...................................................................................................... D. splendidus Sheng, 2002

– Anterior half of mesopleuron with dense punctures. Fore and middle coxae black or brown ....... 22

22. Propodeum with dense punctures and setae, lateromedian longitudinal carinae absent. Basal 2 ridges of dorsal lobe of lower valve of ovipositor strongly curved medially .............. D. fortis Sheng, 2002

– Propodeum with correspondingly sparse punctures and setae, lateromedian longitudinal carinae distinctly present. Basal ridges of dorsal lobe of lower valve of ovipositor straight or slightly curved ............................................................................................................................................. 23

23. Coxae brown to red brown. Lateromedian longitudinal carinae of propodeum reaching to posterior 0.25 ................................................................................................................. D. dux (Tschek, 1869)

– Coxae black. Lateromedian longitudinal carinae of propodeum weak, at most reaching to middle of propodeum ...................................................................................................................................... 24

24. Tergites 2 and 3 each longer than posterior width. Mesosternum black ............................................. ............................................................................. D. melanomerus macropunctatus ( Uchida, 1928)

– Tergite 2 as long as posterior width. Tergite 3 quadrate or transverse. Mesosternum yellow brown or black ................................................................................................................................................ 25

25. Propodeum ( Fig. 7 ) almost as long as maximum width, slightly expanded medially. Tergite 2 ( Fig. 8 ) 0.9 × as long as posterior width. Mesosternum ( Fig. 1 ) yellow brown or black ................................ .......................................................................................................... D. juglanse Sheng & Li sp.nov.

– Propodeum (Fig. 13) distinctly longer than maximum width, median portion not expanded. Tergite 2 (Fig. 14) 1.1–1.2 × as long as posterior width. Mesosternum entirely black .................................. ............................................................................................................. D. nakamurai ( Uchida, 1928)

Figures

Figs 1–3. Dolichomitus juglanse Sheng & Li sp. nov., ♀, holotype (CBDPC). 1. Habitus, lateral view. 2. Head, anterior view. 3. Head and pronotum, lateral view.

Figs 4–7. Dolichomitus juglanse Sheng & Li sp. nov., ♀, holotype (CBDPC). 4. Head, dorsal view.

Figs 8–12. Dolichomitus juglanse Sheng & Li sp. nov. 8–10. ♀, holotype (CBDPC). 8. Metasoma, dorsal view. 9. Apical portion of ovipositor, lateral view. 10. Fore wing. 11–12. ♂, paratype (CBDPC). 11. Habitus, lateral view. 12. Apical portion of metasoma, lateral view. 13–14. Dolichomitus nakamurai (Uchida, 1928), ♀ (CBDPC). 13. Propodeum, dorsal view. 14. Metasoma, dorsal view.