A new species of Gonatopus Ljungh, 1810, G. jaliscanus sp. n., from Jalisco, Mexico, is described and illustrated. In the Neotropical region, G. jaliscanus is similar to G. forestalis Olmi, 1998, but it is distinguished by the black mesosoma (except prothorax, mesoscutum, and mesoscutellum that are yellow), and the metapostnotum being granulated and not rugose; in G. forestalis the mesosoma is completely black and the metapostnotum is granulated and strongly rugose. In the Nearctic region, the new species is morphologically similar to G. curriei Krombein, 1962, but it is distinguished by the dull and granulated metapostonotum; in G. curriei the metapostnotum is shiny and unsculptured. The new species belongs to Gonatopus group 7. The keys to the females of the Nearctic and Neotropical species of this group are modified to include the new taxon.

Chrysidoidea , Gonatopodinae , keys, taxonomy

Dryinidae (Hymenoptera: Chrysidoidea) are parasitoids and often also predators of leafhoppers, planthoppers and treehoppers (Hemiptera, Auchenorrhyncha) (Guglielmino et al. 2013). They comprise 16 subfamilies, 50 genera and more than 1800 species worldwide (Olmi and Xu 2015, Tribull 2015).

Jalisco is a state of Mexico situated in a transition area between the Nearctic and Neotropical regions. Species of Dryinidae collected in this state can belong to either region, so for the identification, researchers have to check the keys of both zoogeographical regions. Dryinidae of the Nearctic and Neotropical regions were studied mainly respectively by Olmi (1984) and Olmi and Virla (2014).

In the Nearctic and Neotropical regions respectively, the genus Gonatopus Ljungh, includes 51 (Olmi 1984, 1987, 1992, 1993, 1995, 2003, 2010, Olmi and Guglielmino 2013) and 127 species (Martins and Domahovski 2017a, b, Martins et al. 2015a, b, Martins and Krinski 2016, Olmi and Guglielmino 2016, Olmi and Virla 2014). For its part, Mexico is inhabited by 135 species of Dryinidae and 25 of Gonatopus (Moya-Raygoza and Olmi 2010, Becerra-Chiron et al. 2017). In 2017 the authors examined a species of Gonatopus collected in Jalisco, Mexico, which is described as new below.

The description follows the terminology used by Guglielmino et al. (2016, 2018a, b) and Olmi and Virla (2014). The measurements reported are relative, except for the total length (head to abdominal tip, without the antennae), which is expressed in millimetres. In the descriptions POL is the distance between the inner edges of the lateral ocelli; OL is the distance between the inner edges of a lateral ocellus and the median ocellus; OOL is the distance from the outer edge of a lateral ocellus to the compound eye.

The term “metapectal-propodeal complex” is here used in the sense of Kawada et al. (2015). It corresponds to the term “metathorax + propodeum” sensu Olmi (1984) and Olmi and Virla (2014). In apterous Gonatopodinae the terms “anterior surface of metathorax + propodeum” and “posterior surface of metathorax + propodeum”, sensu Olmi (1984, 1994), Olmi and Virla (2014), Olmi and Xu (2015) and Xu et al. (2013), correspond here respectively to “metapostonotum” and “first abdominal tergum”, sensu Kawada et al. (2015).

The types of all Nearctic and Neotropical species of Gonatopus were examined. The material studied in this paper will be deposited in the National Museum of Natural History, Washington, DC, USA (USNM).

The description of the new species is based on the study of only a single specimen. The authors are aware that descriptions of new taxa should normally be based on more individuals. However, Dryinidae are so rare that it is uncommon to collect more than one specimen of each species. In addition, on the basis of the experience and knowledge of the authors, the new species is sufficiently delimited by unique characters to justify its description.

Species of Gonatopus from Mexico are known mainly through the monographs on Dryinidae of the Nearctic (Olmi 1984) and Neotropical regions (Olmi and Virla 2014), the checklist of Moya-Raygoza and Olmi (2010) and the paper of Becerra-Chiron et al. (2017) totalling 25 species of Gonatopus from the country. Following the above description of G. jaliscanus, the Gonatopus species known from Mexico now number 26.

In Brazil, there are 31 described Gonatopus species (Olmi and Virla 2014, Martins et al. 2015a, b, Martins and Krinski 2016, Martins and Domahovski 2017a, b); in Costa Rica 22 (Olmi and Virla 2014); and in Argentina 47 (Olmi and Virla 2014). The higher numbers of Gonatopus species from Brazil and Argentina suggest that the true number of species in Mexico will ultimately be much higher. Further research, also on the hosts, will be needed to better characterise this fauna. In fact, hosts are known only for 12 of the 26 Gonatopus species recorded from Mexico (Becerra-Chiron et al. 2017, Guglielmino et al. 2013): another gap to be bridged, in spite of the contributions of Prof Moya-Raygoza and his research group (Moya-Raygoza and Olmi 2010, Becerra-Chiron et al. 2017). Among these 12 hosts, leafhopper pests of maize in the Neotropical region are economically important (Guglielmino et al. 2006).

We offer many thanks to Prof James B. Woolley and Dr Karen Wright (Texas A&M University, College Station, USA) for the loan of the specimen described in this paper. The authors are very grateful to Prof Maurizio Biondi (University of L’Aquila, Italy) for the multifocal pictures of the new species and Mr Bob Zuparko (Essig Museum of Entomology, University of California, Berkeley, California, USA) for his suggestions on the English language of this paper. This research was carried out in the frame of the MIUR (Italian Ministry for Education, University and Research) initiative “Department of excellence” (Law 232/2016) and partially supported by the European Commission under the Grant Agreement number 774571 (project PANTHEON - “Precision farming of hazelnut orchards”).