Dendrocerus Conostigmus Dendrocerus Conostigmus C. lepus C. triangularis Conostigmus Dendrocerus D. punctipes D. penmaricus C. fasciatipennis Conostigmus Dendrocerus Conostigmus Dendrocerus Dendrocerus Conostigmus Dendrocerus C. fasciatipennis Conostigmus Dendrocerus Dendrocerus D. carpenteri D. conwentziae Conostigmus C. fasciatipennis Dendrocerus A Taxonomic Revision of Nearctic Conostigmus (Hymenoptera: Ceraphronoidea: Megaspilidae) Trietsch, Carolyn Mikó, István Ezray, Briana Deans, Andrew R. Zootaxa 2020 2020-06-15 4792 1 1 155 62MYC Dahlbom 1858 [399,550,225,251] Insecta Megaspilidae Conostigmus Animalia Hymenoptera 146 147 Arthropoda genus    Dendrocerusand  Conostigmuscan be incredibly difficult to distinguish ( Mikó et al., 2011). There are both  Dendrocerus-like  Conostigmusspecies (including  C. lepusand  C. triangularis) and  Conostigmus-like  Dendrocerusspecies (such as  D. punctipesand  D. penmaricus). It is unclear to which genus  C. fasciatipennisbelongs. Dessart (1972b)kept the species within the genus  Conostigmusbased on the presence of the medioventral conjunctiva (medioventral conjunctiva always absent and parossiculi fused with the gonostipes in  Dendrocerus). Dessart (1972b)also noted its cylindrical male flagellomeres, which were typical of  Conostigmus. However, this species also lacks a facial pit (absent in most  Dendrocerus) and has a  Dendrocerus-like obtuse ocellar triangle in males (POL greater than LOL), where the two posterior ocelli are closer to the compound eyes than to each other (POL greater than OOL). Molecular data has so far been unable to delimit  Conostigmusand  Dendrocerusand determine the generic placement for  C. fasciatipennis. Based on preliminary ultraconserved element (UCE) data,  Conostigmusis paraphyletic and  Dendrocerusis polyphyletic, with a few  Dendrocerusspecies (  D. carpenteriand  D. conwentziae) nested within  Conostigmusand  C. fasciatipennisseparating those species from the rest of  Dendrocerus(Blaimer et al., in prep.).  Some commonly-used morphological characters for distinguishing  Conostigmusand  Dendrocerusmales are the ocellar ratios and the shape of the ocellar triangle ( Dessart, 1995b; Dessart and Cancemi, 1987).  Dendrocerusmales are usually distinguished as having an obtuse ocellar triangle (POL greater than LOL) where the two posterior ocelli are closer to the compound eyes than to each other (POL greater than OOL), whereas  Conostigmusmales are usually thought to have an acute or equilateral ocellar triangle (POL equal to or less than LOL) where the posterior ocelli are closer to each other than to the compound eyes (POL less than OOL). However, this does not hold true for all  Conostigmus. Some species have more obtuse ocellar triangles (POL greater than LOL) in the males, including  C. nigrorufus,  C. duncani, and  C. bipunctatus. Some male  Conostigmuseven have the posterior ocelli closer to the compound eyes than to each other (POL greater than OOL), including  C. lepusand  C. triangularis. As of now, there are no known  Dendrocerusspecies with  Conostigmus-like ocellar ratios, but more revisionary work on  Dendrocerusis needed to investigate this before a conclusion can be made. Male antennal characters are also commonly used for distinguishing between  Dendrocerusand  Conostigmus( Dessart, 1995b; Dessart and Cancemi, 1987). Female antennae are indistinguishable between the two genera, but male antennae of  Conostigmusare symmetrical and cylindrical in shape, whereas the male flagellomeres of  Dendrocerusare usually asymmetrical and can be serrate or trapezoidal. Some  Dendrocerusalso have branched flagellomeres (  D. mexicaligroup), a state which is never found in  Conostigmus( Dessart, 1995a, 1995b, 1999, 2001). Of course, there are some exceptions in  Dendrocerus. Both the  D. penmaricusspecies group and the  D. punctipesspecies group have symmetrical, cylindrical male flagellomeres that resemble those of  Conostigmus( Dessart, 1983b, 1995a). Members of the  D. penmaricusgroup can be differentiated from  Conostigmusby the maximum scape width, which is greater than the pedicel length in  D. penmaricusspecies group members (maximum scape width less than pedicel length in all  Conostigmus) ( Dessart, 1995a). The  D. punctipesspecies group is more difficult to distinguish from  Conostigmus, but can be differentiated by the combination of the fused parossiculi, absence of the facial pit, and  Dendrocerus-like ocellar triangle ( Dessart, 1983b). Though the characters discussed above can be useful for distinguishing male  Conostigmusand  Dendrocerusspecimens, they should not be used individually to make an identification. We recommend using a combination of characters to distinguish genera due to the numerous exceptions and overlap between these two genera. In addition to the characters above, some useful characters include the presence of the sternaulus (always absent in  Dendrocerus, but present or absent in  Conostigmus), wing presence (wings never absent in  Dendrocerus, but present or absent in  Conostigmus), notauli posterior end (always adjacent to the transscutal articulation in  Conostigmus, but not adjacent in some  Dendrocerus) and male genitalia characters including the presence of the parossiculi (parossiculi fused with the gonostipes in  Dendrocerusbut never in  Conostigmus) and the medioventral conjunctiva of the gono-style–volsella complex (parossiculi never independent in  Dendrocerus, but independent or fused in  Conostigmus). ( Dessart, 1985, 1995a, 1995b, 1999, 2001; Mikó et al., 2011, 2013). The facial pit is present in most  Conostigmus(exceptions include  C. dimidiatusand  C. erythrothorax) and absent in most  Dendrocerus(exceptions include  D. carpenteri,  D. flavipesand  D. rectangularis). Other characters that can be useful but are more subjective include metapleural sulcus shape (usually curved in  Dendrocerusand straight in  Conostigmus, though it appears curved in some  Dendrocerus-like  Conostigmussuch as  C. lepusand  C. triangularis), as well as head shape (usually triangular in  Dendrocerusand globulose or circular in  Conostigmus).