Ismarus Haliday, 1835

Zhang, Xiao, Chen, Hua-yan, Liu, Jing-xian & Luo, Shi-xiao, 2021, The genus Ismarus Haliday (Hymenoptera, Ismaridae) from China, Journal of Hymenoptera Research 82, pp. 139-160 : 139

Ismarus Haliday, 1835

Ismarus Haliday, 1835: 467. Type species Cinetus dorsiger Haliday, 1831, by monotypy.

Entomia Herrich-Schäffer, 1840: 127. Type species Entomia campanulata Herrich-Schäffer, 1840, by monotypy.

Agonophorus Dahlbom, 1858: 289. Type species Ismarus rugulosus Förster, 1850, designated by Muesebeck (1972).

Remarks.

In the revision of the New World Ismarinae (then was treated as a subfamily of Diapriidae and contained the only genus, Ismarus ), Masner (1976) pointed out that Ismarus "is usually characterized by the low insertion of antennae, transverse head, and the absence (better reduction) of notauli". This suggests that he was not certain about the status of notauli within the genus. However, in the key to subfamily of Diapriidae and the descriptions of the New World species, he continued to state that "notauli were always present but reduced to anterior pits". Subsequent researchers followed Masner’s diagnosis of the genus and described these pits as notauli ( Liu et al. 2011; Kolyada and Chemyreva 2016; Kim et al. 2018a, b), except Kolyada and Chemyreva (2016) described the anterior pits as the reduced notauli and the rest of the pits along the anterolateral margin of mesoscutum as part of the mesoscutual suprahumeral sulcus. We here examine these pits (Fig. 1A, B ) using scanning electron microscopy and compare them with the notauli in a species of Coptera Say ( Diapriidae ), which has typical notauli (Fig. 1C ). The pits in Ismarus are along the anterolateral margin of mesoscutum where the mesoscutual suprahumeral sulcus is located in many groups of Hymenoptera and are different from the pits of the typical notauli such as found in Coptera. The anterior pits in Coptera is located at the anterior margin of the longitudinal grooves of the notauli and apparently are a part of the notauli, while the pits in Ismarus (if they are present) are parallel to the anterolateral margin of the mesoscutum and never present as a part of any longitudinal grooves of the tmesoscutum. Therefore, we here conclude that the pits present along the anterolateral margin of the mesoscutum in Ismarus constitute part of the mesoscutual suprahumeral sulcus and are not notauli. The mesoscutual suprahumeral sulcus can be totally absent (as in Ismarus dorsiger (Haliday)), present as a single pit on each side (as in Ismarus halidayi Foerster, Fig. 1B ), or present as a few pits of varying size (as in Ismarus nigritrochanter Liu, Chen & Xu, Fig. 1A ).

Figures

Figure 1. Mesosoma, dorsal view, mshs: mesoscutual suprahumeral sulcus; nt: notaulus A Ismarus nigritrochanter Liu, Chen & Xu B Ismarus halidayi Foerster C Coptera sp.