Ophion obscuratus Fabricius, 1798

Johansson, Niklas & Cederberg, Björn, 2019, Review of the Swedish species of Ophion (Hymenoptera: Ichneumonidae: Ophioninae), with the description of 18 new species and an illustrated key to Swedish species, European Journal of Taxonomy 550, pp. 1-136 : 83-84

Ophion obscuratus Fabricius, 1798

Figs 7F, H, L, N , 10A

Ophion obscuratus Fabricius, 1798: 237 .

Ophion obscurus Fabricius, 1804: 132 .

Ophion flavolineatus Brullé, 1846: 147–148 .

Material examined

Lectotype, ♂, of O. obscuratus ( ZMC); lectotype, unsexed, of Ophion flavolineatus ( MNHN); 12 ♀♀, 31 ♂♂ ( Sweden); 5 ♀♀, 3 ♂♂ ( Britain ); 1 ♀, 2 ♂♂ ( Germany).

Diagnosis

Fore wing length 16–18 mm. Antenna with 62–66 flagellomeres. Central flagellomeres in males about 1.3 times as long as wide ( Fig. 7N ). Subapical flagellomeres approximately 1.5–1.6 times as long as wide. Temples slightly buccate. Head in lateral view with temple 0.7–0.8 times as long as compound eye in females and 0.5–0.6 times in males. Gap between compound eye and lateral ocellus usually distinct, about 0.3 times the diameter of ocellus. Occipital carina almost straight in its lower part joining hypostomal carina at an angle of 45–60 degrees ( Fig. 7L ). Malar space about 0.2 times as long as mandibular base in female and male. Mandibular gape right-angled, with internal angles. Wing membrane clear. Ramellus usually short, reaching 0.1–0.3 times the width of the discosubmarginal cell. Radius sinuous. Structure of mesopleuron similar to that of Ophion slaviceki , shining or weakly shagreened with weaker, very regular punctation consisting of small punctures. Interstices between punctures about equal to their diameter, up to 2 times their diameter. Epicnemial carina, in antero-ventral view, with pleurosternal angles obviously anterior to sternal angles. Sternal angles rounded, epicnemial carina between sternal and pleurosternal angles usually less concave than in O. variegatus . Pleurosternal angles rounded, obtuse, rarely right angeled. Scutellum wide, without lateral carinae. Structure of propodeum similar to that of O. luteus ( Fig. 10A ). Posterior to anterior transverse carina mostly shining. Anterior transverse carina always present centrally anterior to area superomedia, but often also present laterally, though rarely strongly raised. Posterior transverse carina usually only present laterally, widely interrupted centrally ( Fig. 10A ). Central longitudinal carinae weak or absent, when present forming a narrow triangular area. Hind trochantellus shorter than wide in dorsal view. Legs normal with hind femur about 6.0–7.0 times as long as wide. Hind trochantellus usually longer than in other species except O. luteus , O. slaviceki and O. variegatus ( Fig. 7F ). Slightly shorter than wide in dorsal view. Inner spur of hind tibia long about 0.3–0.4 times as long as metatarsus. Sclerotised section of first sternite ending level with spiracle.

Colour

Body usually more brownish than other species and with extensive whitish pattern on thorax (as in Fig. 11 A–B) and metasoma. Mandibular teeth black. Ovipositor sheath testaceous.

Ecology

Ophion obscuratus occurs in areas with favorable climate in Southern and Central Sweden, preferably in open or semi-open grasslands and heaths during October to December. Due to the late period of flight it has been overlooked and the relatively low number of collected specimens probably does not reflect the real abundance of this species.

Distribution in Sweden

Probably widespread, at least in Southern Sweden.

Remarks

This species has often been treated as conspecific with Ophion variegatus and the two species have been regarded as two different, but slightly morphologically different generations. Ophion obscuratus is usually easily separated from O. variegatus by the shape of the junction between the occipital and hypostomal carinae ( Fig. 7L ), larger size (fore wing length 16–18 mm), more numerous flagellomeres (62–66), the usually wider scutellum and the shape of the flagellomeres. Brock (1982) refers to Ophion obscuratus as “autumnal giants”. The interpretation of the lectotype male of Ophion obscuratus , despite the rather poor shape of the specimen, is that it represents the larger autumnal species based on the large size and shape of the occipital carina. For further taxonomic comments, see Discussion: “The Ophion obscuratus aggregate”.

Figures

Fig. 7. A–D. Occipital carina posterior view. A. Ophion confusus Johansson sp. nov., holotype, ♀ (NHRS-HEVA000008637). B. O. mocsaryi Brauns, 1889. C. O. ocellaris Ulbricht, 1926. D. O. areolaris Brauns, 1889. E–G. Hind trochanter and trochantellus dorsal view. E. O. slaviceki Kriechbaumer, 1892. F. O. obscuratus Fabricius, 1798. G. O. costatus Ratzeburg, 1848. H–I. Mandible ventral view. H. O. obscuratus. I. O. slaviceki. J–K. First tergite, aberration O. artemisiae Boie, 1855. J. Dorsal view. K. Lateral view. L–M. Head in posterior view showing generalized shape of occipital carina. L. O. obscuratus. M. O. variegatus Rudow, 1883. N–O. Central flagellomeres in males. N. O. obscuratus. O. O. variegatus.

Fig. 10. Generalized carination of propodeum in females, posterodorsal view. A. Ophion luteus (Linnaeus, 1758)/O. scutellaris Thomson, 1888/O. obscuratus Fabricius, 1792. B. O. costatus Ratzeburg, 1848. C. O. brocki Johansson sp. nov., paratype, ♀ (NHRS-HEVA000008633). D. O. confusus Johansson sp. nov., holotype, ♀ (NHRS-HEVA000008637). E. O. crassicornis Brock, 1982. F. O. artemisiae Boie, 1855. G. O. ellenae Johansson sp. nov., paratype, ♀ (NHRS-HEVA000008655). H. O. perkinsi Brock, 1982. I. O. ocellaris Ulbricht, 1926. J. O. areolaris Brauns, 1889. K. O. dispar Brauns, 1895. L. O. tenuicornis Johansson sp. nov., paratype, ♀ (NHRS-HEVA000008743). M. O. longigena Thomson, 1888. N. O. brevicornis Morley, 1915. O. O. forticornis Morley, 1915.

Fig. 11. Head and mesosoma, lateral and dorsal view of female. A‒B. Ophion variegatus Rudow, 1883. C‒D. O. ventricosus Gravenhorst, 1829.