Gerbillitaenia, Haukisalmi & Elmahy, 2025

Gerbillitaenia gen. nov.

Etymology: “ Gerbillitaenia ” refers to gerbils ( Gerbillinae ), the hosts of the new genus.

Diagnosis: Strobila longitudinally elongate, with relatively small number of proglottids. Anterior end of strobila blunt, widening rapidly. Scolex not distinctly separate from neck region. Osmoregulatory system consists of multiple narrow, anastomosing longitudinal canals. Genital pores usually regularly alternating, positioned near anterior margin of proglottid. Testes numerous, appearing as two wide lateral groups. Cirrus sac slender, poorly delimited from vas deferens. Distinct internal and external seminal vesicles absent. Ovary median or slightly poral, with lobules pointing in all directions except spaces occupied by lateral genital ducts and anterior uterine trunk. Vitellarium poral, usually transversely elongate and slightly curved, but not distinctly bilobed. Longitudinal axis of vitellarium inclined slightly anteriorly with respect to longitudinal axis of proglottid. Vagina slender, of uniform width, distinctly longer than cirrus sac. Distinct elongate seminal receptacle present. Pregravid uterus with long longitudinal trunk and several bifurcating branches pointing laterally and postero-laterally; posterior branches form prominent fan-shaped group without distinct trunk. In gerbils ( Muridae : Gerbillinae ). Type and only species: G. psammomi ( Mikhail & Fahmy, 1968) n. comb.

Remarks. Gerbillitaenia gen. nov. differs from Skrjabinotaenia s. s. with respect to the shape of the strobila, width of the testicular field and ovary and structure of the ovary and uterus. Compared with the latter genus, Gerbillitaenia gen. nov. has a more prominent anterior strobila, wider testicular fields with more numerous testes, a less extensive ovary with few anterior lobules and without the antero-poral lobe, and a fully developed (pregravid) uterus with a longer trunk with several bifurcating secondary branches and a fan-shaped posterior group of uterine branches. In addition, there appears be a difference in the inclination of the vitellarium (inclined slightly anteriorly in Gerbillitaenia gen. nov., posteriorly in Skrjabinotaenia s. s.).

Based on Elmahy (2022), the presence, distribution and structure of two types of cuticular microtriches (filitriches and spinitriches) are different in G. psammomi (as S. oranensis ) and S. gerbilli , which provides an additional evidence for the distinction between Gerbillitaenia gen. nov. and Skrjabinotaenia s. s.