Ophion Fabricius 1798
- Dataset
- Review of the Swedish species of Ophion (Hymenoptera: Ichneumonidae: Ophioninae), with the description of 18 new species and an illustrated key to Swedish species
- Rank
- GENUS
- Published in
- 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: 1-136, DOI: 10.5852/ejt.2019.550
Classification
- kingdom
- Animalia
- phylum
- Arthropoda
- class
- Insecta
- order
- Hymenoptera
- family
- Ichneumonidae
- genus
- Ophion
description
Barcoding results 234 specimens produced barcodes (out of an attempted 284) (Fig. 1). A full barcode sequence (658 bp) was recovered from 115 specimens, sequences greater than 500 bp from 95 specimens and shorter sequences from 24 specimens. Specimens included in the analysis with a barcode shorter than 500 bp is marked with an * in Fig. 1. Full length barcodes or barcodes with more than 630 bp, were recovered from at least one specimen for all species except O. obscuratus, O. autumnalis Johansson sp. nov. and O. kallanderi Johansson sp. nov. A sequence from O. vardali Johansson sp. nov. containing 401 bp was acquired from NorBOL project DS-ICHNN. No Swedish specimens of O. forticornis and O. subarcticus were sequenced due to the absence of material suitable for sampling. An additional sequence from Ophion forticornis retrieved from the dataset of Schwarzfeld et al. (2016) at https: // datadryad. org / resource / doi: 10.5061 / dryad. 49 g 98 was included in the phylogenetic analysis. Barcode records for the sampled specimens are available in the BOLD dataset “ STI-NJBC ”. The barcoding in combination with the morphological analysis confirms and supports the existence of a majority of the species defined in this study and indicates the existence of at least three additional potentially cryptic species (Fig. 1). The sequencing also supports the aggregate nature of several species by small, but consistent genetic differences. This particularly concerns the aggregates around Ophion luteus (Fig. 3), O. perkinsi (Fig. 4) and O. inclinans Johansson sp. nov. (Fig. 5). Assessment of morphological characters used in species delimitation When it comes to morphological characters used in definition and separation of species, there are some new characters highlighted in this study that have been used in combination with more well known features used by previous authors to delimit species. Body size The size of the body is a character that can be used to identify some species in combination with other morphological features. As the metasoma often is bent in various postitions the size is usually indicated by the length of the fore wing. There is always some variation in size between individuals and frequently unusally small specimens are encountered. These are probably either the result of starved specimens or specimens reared from smaller host-species. Head The distance from the outer margin of the lateral ocellus to the nearest inner margin of the compound eye (the ocellar-ocular interspace) (Figs 14 A – B, 18 A – B) has been regarded as an important feature by several previous authors (Gauld 1973; Brock 1982; Broad 2012). The ocellar-ocular interspace is somewhat variable within species but in many species quite characteristic, indeed making it a rather useful character in species separation. The ocellar-ocular interspace often has a relation to the length of the temple / the length of the compound eye ratio, which is another useful feature (Figs 15 E – G, 19 B, D, F). The importance of this character has been underestimated by previous authors. While the shape and the length of the temple usually is assessed in dorsal view, this perspective and the percieved length of the temple can be strongly affected by only a slight change in the angle of view. A lateral view is often a better way to appreciate the ratio. The length of the malar space, i. e., the shortest distance between the lower margin of the compound eye to the mandibular base, in relation to the width of the mandibular base, is often used in species definition (Jussila 1965; Brock 1982). It is a quite consistent character within species, though sometimes hard to appreciate in detail and seemingly more variable in males than in females. The sulcus, i. e., the elongate groove, behind the lateral ocelli (Fig. 15 B), can be diagnostic. In some species it is particularly well defined and useful as a complementary character in species definition (Brock 1982). The importance of the shape of the occipital carina (Fig. 7 A – B) has been partly overlooked by previous authors and is quite useful in species definition, mainly used in combination with other characters. Dorsally it can be angled, medially dipped or straight. Also the shape of occipital carina before the junction beween the occipital and hypostomal carina can be useful for some closely related species pairs (Izquierdo 1984). A feature which is very useful, but rarely previously used to any extent in the diagnosis of Ophion species, is the shape of the head in anterior view and the relation between the width of the face and the compound eye, often also supported by the shape of the clypeal area (Schwarzfeld & Sperling 2014). As the shape of the temples treated above, the importance of this character has been obscured by the aggregate nature of some species. The human ability of facial recognition can be a valuable asset when trying to separate closely related species. The sculpture of the face, i. e., the intensity and size of the punctation and the surface being more or less shagreened, is a somewhat variable character in many species, but nevertheless very useful in defining morphospecies if treated in combination with other characters. The mandibular gape, i. e. the angle between the two mandibular teeth (Fig. 7 H – I), is useful in separating some closely related species in some subgroups, but only when exhibiting a distinct difference, i. e., the gape forming an acute angle vs an obtuse or right angle (Morley 1915; Brock 1982; Broad 2012; Broad et al. 2015;). A secondary character to be noted is that species attacking hosts pupating under ground often have the mandibles more or less worn from emerging through soil, indicating an ecological characterization that sometimes can be useful in indicating the species involved. Antennae The length and shape of the flagellomeres and the number of flagellomeres has been shown to be of significance in the separation of species in some aggregates (Figs 7 N – O, 8 A – F, 8 M – O). The number of flagellomeres, though slightly variable within species, seems to be a good way to delimit species groups and sometimes also closely related species (Brock 1982; Broad 2012). The relative length and width of the flagellomeres, as well as the pilosity of the flagellomeres seem to be quite consistent within some species and also between the sexes. Mesosoma The structure of the mesoscutum and mesopleuron is often quite typical, but not particularly often previously used for the separation and definition of species. Although variable to some extent within species, it is diagnostic in others and sometimes also useful in separating closely related species. The length of the scutellar carinae (Fig. 6 A – D) have been of taxonomic importance primarly to separate species within the wider definition of the O. luteus group as defined by Gauld (1985). The extension of the carinae can be slightly variable within species but it is still an important character for species definition (Thomson 1888; Brock 1982; Gauld 1978). The shape of the scutellum in dorsal, and sometimes lateral view, can also contribute to the determination. The sides of the scutellum can be more or less converging and the scutellum more or less convex in lateral view. A very useful character when it comes to definition of morphospecies is the shape of the epicnemial carina (Brock 1982; Broad 2012). The shape of the pleurosternal angles and their position in relation to the sternal angles in anteroventral view (Fig. 9 A – I) is often typical and relatively constant within species groups or sometimes within single species (Brock 1982; Broad 2012). Another characteristic that can be used in species diagnostics is the shape of the propodeal carinae (Figs 10 A – O, 14 C – D, 18 E – F). The carinae can be more or less well developed in single individuals, but the interspace and angles between the carinae are quite consistent within species. Due to the individual variation in the development of the carinae, its taxonomic use has been somewhat underestimated. Wings The presence / absence and relative length of the ramellus in the fore wing (Fig. 16 A – B) and the nervellus in the hind wing being broken at, above or below the middle by the discoidella (Fig. 13 E – F) have been used by previous authors (Brock 1982; Broad 2012; Broad et al. 2015) and especially the latter can be useful in the separation of species. Brock (1982) regards this character as unstable and thereby less useful, which is the result of the misinterpretation of some species by the author. The shape of the radius in the fore wing can be diagnostic as it can be evenly curved or more or less sinuous (Fig. 13 A, C). This character seem to be more stable in females than in males. Legs The shape of the legs, e. g., the ration between the length and the width of the femur, tarsus and trochantellus, is often useful in separating som species or species groups (Gauld 1978; Brock 1982). Notable is also the length of the hind tibial spurs in relation to the length of the hind metatarsus (Brock 1982). Metasoma A character that is particularly useful when defining species is the relative positioning of the spiracle of the first tergite in relation to the hind margin of the sclerotised section of the first sternite (Fig. 6 E – H) (Brock 1982; Broad 2012). The spiracle can be situated level with, or more or less posterior to the hind margin on the sclerotised part of the sternite. Some variability in this character will usually make it necessary to combine it with other characters, such as the carination of the lateral margins of the scutellum. The shape of the first tergite in lateral view (Fig. 20 E – F) as well as the prescence or absence of a dorsal undulation is also quite consistent and useful. The shape of the male genitalia is usually quite similar between species and parameres are often deformed by being stored in ethanol or if dried up. However, in some cases the shape of the parameres in lateral view can be useful in the separation of species (Fig. 6 I – J). Colour Even though known for their lack of diagnostic colouration, there are some colour characters in Ophion that can provide information regarding the identification of certain species. The colouration of the head, mesosoma and metasoma have been used to primarily define species with extensive black or pale markings. For some species groups, the colour of the ovipositor sheath is a very useful distinguishing character used in this study. The colour of the stemmaticum can be of some importance when separating the two species within the subgenus Platophion Hellén, 1926. While the darker or brownish colouration of the mesosoma and coxae in some species can be rather variable it is found to be quite constant in others, thereby being partly diagnostic. In some species more subtle colour characters, such as the prescence / absence or the distribution of the paler areas around the compound eyes and scutellum, can provide some information that can contribute to species diagnostics.
Name
- Homonyms
- Ophion Fabricius 1798
- Ophion