First description of the metopiine genus Trieces Townes, 1946 (Hymenoptera: Ichneumonidae) from the Indomalayan region with three new species from India

Abstract

Trieces Townes, 1946 is one of the largest metopiine genera for which species have been described from all zoogeographical regions except the Indomalayan. The present study reports a major range extension of Trieces with the description of three new species from India. The described species are members of the onitis species group. An identification key to the Palearctic and Indomalayan species of the onitis group is included with the revised generic diagnosis and a key to separate Trieces from its closest genus Chorinaeus. Distribution pattern and character plasticity of Trieces are also discussed.

A new Darwin wasp genus, Soliga (Hymenoptera: Ichneumonidae: Metopiinae), from India

“…Until now only 24 metopiine species belonging to eight genera are known from India (Yu et al 2016). The new distribution of several genera like Acerataspis, Chorinaeus and Trieces evidently support the rich diversity of metopiines in this region (Ranjith & Priyadarsanan 2022;Ranjith unpublished data). Though metopiine species are reported from a wide elevational gradient (0-4100 m a.s.l.…”

“…Most genera of the subfamily Metopiinae show rather wide distribution except some endemic genera like Hemimetopius Benoit, 1955 (Afrotropical), Sciron (Australian region), Bothromus Townes & Townes, 1959 (Nearctic), Cubus, Forrestopius and Ojeulos (Neotropical) (Yu et al 2016). The recent discovery of Trieces from the Oriental region and new generic distribution record of metopiine genera from the Eastern Palaearctic and Oriental regions further support this argument (Choi et al 2016b;Ranjith & Priyadarsanan 2022). Until now only 24 metopiine species belonging to eight genera are known from India (Yu et al 2016).…”

“…Character like presence or absence of fore wing areolet is another variable character within the genera of Metopiinae (Fitton 1984) as three genera Leurus Townes, 1946, Sciron and Triclistus are polymorphic for this character. In conclusion the intergeneric classification of Metopiinae is somewhat unstable due to indistinct delimitation of genera like Chorinaeus and Trieces (Ranjith & Priyadarsanan 2022) and Hypsicera and Stethoncus (Broad et al 2018). Most of the regional revisions did not yield a clearer picture about the supraspecific relationships rather than some informal comments.…”

“…Gauld & Wahl (2006) synonymized Apolophus under ctenopelmatine genus Scolomus Townes & Townes, 1950 and transferred into Metopiinae. Recent observations revealed that new distribution records of the genera Acerataspis Uchida, 1934, Chorinaeus Holmgren, 1858and Trieces Townes, 1946 reflect a rich diversity in India (Ranjith & Priyadarsanan 2022;Ranjith unpubl. data).…”