Anthocorini Fieber, 1836

Yamada, Kazutaka & Yasunaga, Tomohide, 2021, The tribe Anthocorini in Japan (Hemiptera: Anthocoridae): descriptions of new species, review of distribution and bionomics, Acta Entomologica Musei Nationalis Pragae 61 (2), pp. 375-426 : 376-377

Tribe Anthocorini Fieber, 1836

Diagnosis. Anthocorini is primarily recognized by a combination of the following characters: Macrochetae on head and pronotum absent or indistinct; antennal segments III and IV generally fusiform, almost same width as segment II; length of each seta less than twice the diameter of the segment; pronotal collar generally wide and distinct; fossula spongiosa present on apex of pro- and mesotibiae, sometimes on the metatibiae; protibiae lacking teeth on ventral surface; protarsi always with pulvillus; male abdominal segment VIII symmetrical; paramere variable in shape, but generally horn-shaped or falcate; endosoma very long, in the form of a copulatory fiber, covered with small spinules; ectospermalege formed as copulatory tube; copulatory tube opens to the exterior on ventral side between abdominal segments VII and VIII, membranous and very long, correlated with the length of endosoma; and sperm pouch more or less spherical. Detailed characteristics of the tribe were provided by Cൺඋൺඒඈඇ (1972).

Discussion. The Anthocorini currently contains 11 genera: Acompocoris Reuter, 1875 (Holarctic) , Anthocoris Fallén, 1814 (Northern Hemisphere, with a few exceptions), Arnulphus Distant, 1904 ( Myanmar), Coccivora McAtee & Malloch, 1925 ( USA), Compsobiella Poppius, 1909 (Afrotropical), Elatophilus Reuter, 1884 (Holarctic) , Galchana Distant, 1910 ( India) , Macrotrachelia Reuter, 1871 (Neotropical) , Melanocoris Champion, 1900 ( New World ), Temnostethus Fieber, 1860 (Palaearctic, with one Holarctic species), and Tetraphleps Fieber, 1860 (Holarctic) . The majority of species in the tribe occur in the Holarctic Region, especially the Palaearctic, where approximately 90 species are reported (Pඣඋංർൺඋඍ 1996, AඎKൾආൺ et al. 2013a). Considering the distribution of each species, the Anthocorini seem to have originated in the Palaearctic, with subsequent dispersal to the Oriental and across the Bering Strait into the Nearctic (Fඈඋൽ 1979). As stated by Fඈඋൽ (1979), the Anthocorini represent a more recent group than other anthocorid tribes, based on their phylogeny and their distribution pattern. Her opinion is also supported by recent molecular analyses, which suggested that the tribe originated in the Early Cretaceous (JඎඇG & Lൾൾ 2011).

Exhibiting great similarity in the female genitalia (e.g., the ectospermalege formed as copulatory tube, connecting to a spherical sperm pouch), the Anthocorini and the Oriini Carayon, 1958 are presumably derived from a common ancestor. The composition of the copulatory tube is similar in females of the tribes Scolopini Carayon, 1954 and Blaptostethini Carayon, 1972; therefore, these four tribes might form a closely related or a monophyletic group within the Anthocoridae or Cimicoidea. However, their morphological similarity in female genitalia is not in accordance with the recent molecular-based phylogenetic analyses of relationships among these tribes (JඎඇG et al. 2010, JඎඇG & Lൾൾ 2011).

Cൺඋඉංඇඍൾඋඈ & Dൾඅඅൺඉඣ (2008) transferred Dufouriellus Kirkaldy, 1906 from the tribe Dufouriellini to the Anthocorini based on the following: 1) the ocelli placed behind the line of the eyes, 2) antennae with length of each seta less than twice the diameter of the segment, 3) a transverse row of setae on the head absent, 4) tibial teeth or spines absent, and 5) dorsal surface subglabrous (Cൺඋඉංඇඍൾඋඈ & Dൾඅඅൺඉඣ 2008). However, the above diagnostic features 1), 3), and 5), at least, are also found in Scolopina of the Scolopini , and character 4) is also shared with some genera of the Dufouriellini [= Cardiastethini sensu Cൺඋඉංඇඍൾඋඈ & Dൾඅඅൺඉඣ (2008)] and some genera of the Scolopini . In addition, Anthocorini has a unique copulatory mechanism, in which the very long endosoma is in the form of a copulatory fiber and inserts through a very long female copulatory tube to the sperm pouch. These characteristic states are regarded as synapomorphies, which strongly support the monophyly of Anthocorini . The female genitalia of Dufouriellus are reduced and have no ectospermalege- -shaped copulatory tube (lacking ectospermalege itself) (Cൺඋൺඒඈඇ 1972, Pඣඋංർൺඋඍ 1972, Cൺඋඉංඇඍൾඋඈ & Dൾඅඅൺඉඣ 2008; Yamada, unpubl. data). The morphological features proposed to isolate Dufouriellus from Cardiastethini by Cൺඋඉංඇඍൾඋඈ & Dൾඅඅൺඉඣ (2008) seem to be highly homoplastic. Nevertheless, with the exception of Dufouriellus , the Anthocorini are almost certainly monophyletic, based on the above-mentioned synapomorphies. Furthermore, Dufouriellus should not be treated as a member of the Anthocorini until a phylogenetic analysis based on all known genera of Anthocoridae is undertaken.