Pilekiinae Sdzuy, 1955

Pérez-Peris, Francesc, Laibl, Lukáš, Vidal, Muriel & Daley, Allison C., 2021, Systematics, morphology, and appendages of an Early Ordovician pilekiine trilobite Anacheirurus from Fezouata Shale and the early diversification of Cheiruridae, Acta Palaeontologica Polonica 66 (4), pp. 857-877 : 859-860

Subfamily Pilekiinae Sdzuy, 1955

Genera included.— Anacheirurus Reed, 1896 , Chashania Lu and Sun in Zhou et al., 1977, Courtessolium ? Přibyl and Vaněk in Přibyl et al. 1985, Emsurina Sivov in Egorova et al., 1955, Eocheirurus Rozova, 1960 , Koraipsis Kobayashi, 1934 , Landyia Jell, 1985 , Macrogrammus Whittard, 1966 , Metapilekia Harrington, 1938 , Metapliomerops Kobayashi, 1934 , Parapilekia Kobayashi, 1934 , Pilekia Barton, 1915 , Pseudopliomera Lu and Qian in Yin and Li, 1978, Seisonia Kobayashi, 1934 , Sinoparapilekia Peng, 1990 , Tesselacauda Ross, 1951 , Tienshihfuia Lu in Lu et al., 1976, Victorispina Jell, 1985 , Yinaspis Zhang and Fan, 1960 .

Emended diagnosis.— Cheiruridae with thoracic pleura divided into anterior and posterior bands by a deep, long (tr.) pleural furrow; broad (tr.) proximal part of thoracic pleura with fulcrum situated distally 2/3 from the axis; pygidium with at least two first pleural tergites displaying a deep pleural furrow that divide the pleura into anterior and posterior bands, as in the thoracic pleura.

Remarks.— Pilekiinae has been considered as a subfamily of Pliomeridae (Harrington in Moore 1959; Vaněk 1965; Demeter 1973; Peng 1984; Mergl 1984), as a subfamily of Cheiruridae ( Fortey 1980; Přibyl et al. 1985; Edgecombe et al. 1999; Adrain 2013; Adrain and Karim 2019) or as a separate family Pilekiidae ( Sdzuy 1955; Whittington 1961; Jell 1985; Peng 1990; Lee and Chatterton 1997; Ebbestad 1999; Jell and Adrain 2002; Pärnaste 2004; Mergl 2006). In this paper, we consider pilekiids as a subfamily of Cheiruridae . This suggestion is based on Adrain and Karim (2019), who have shown that pilekiids and the rest of cheirurids share a similar morphology of the rostral plate and the hypostome.