Skrjabinotaenia oranensis Akhumyan 1946

Skrjabinotaenia oranensis (Joyeux & Foley, 1930) Akhumyan, 1946 (Figs. 2A, 4; Table 2) Synonyms: Catenotaenia oranensis Joyeux & Foley, 1930, Meggittina numida Jrijer & Neifar, 2014. Material examined: Syntypes of S. oranensis (MHNG 44896–44898, fragments of five specimens) from Meriones shawi (Duvernoy) (Gerbillinae) from Mascara, Département d’Oran, Algeria, and two voucher specimens of M. numida from the same host species from Mezzouna, Tunisia. Deposited voucher specimen: FMNH: KN.7144 (slide) from M. shawi from Tunisia. Deposited DNA sequence: GenBank: MG050043 (nuclear 28S gene) (Haukisalmi et al. 2018). Description: The measurements and counts provided by Joyeux & Foley (1930) and Jrijer & Neifar (2014) are shown in Table 2. Length of strobila 15–20 mm (n=3), maximum width 3.1–4.6 mm (n=4), attained in pregravid or gravid proglottids. Number of proglottids 10–14 (n=4). Anterior end of strobila tapering, widening gradually. Scolex not distinctly separate from neck region. Neck (unsegmented region) short or absent. Suckers 125–173 (n=14) in diameter, divided by longitudinal groove or in contact with each other. Proglottids acraspedote; lateral margins convex, margins between proglottids first slightly convex, then becoming concave and sometimes partly slit medially in terminal proglottids. Proglottids from immature to postmature stage slightly wider than long, shape of pregravid proglottids variable and gravid proglottids distinctly longer than wide. Dimensions of mature proglottids: length 0.7–1.5 mm (n=3), width 1.3–2.1 mm (n=3) and length/width ratio 0.37–0.77 (n=3); dimensions of fully gravid (detached) proglottids: length 3.2–4.2 mm (n=2), width 1.3–2.3 mm (n=2) and length/width ratio 1.8–2.5 (n=2). Osmoregulatory system consists of multiple, narrow, anastomosing longitudinal canals forming ventral and dorsal plexus; lateral genital ducts run between plexuses. Two to three canals from each side of strobila join in scolex. Genitalia single. Genital pores either regularly alternating or irregularly alternating in short series, positioned near anterior margin of proglottid. Genital atrium narrow and shallow. Testes numerous, ca. 230 (n=2) in total number, appearing as two widely separate lateral groups; number of poral and antiporal testes 106–113 (n=2) and 118–125 (n=2), respectively. Cirrus sac slender, 220–400 (n=4) long and 30–70 (n=4) wide in distal part, slightly curved, with delicate wall; distal part of sperm duct (ductus cirri) sinuous or convoluted, proximal part slightly expanded but distinct internal seminal vesicle absent. No armature observed in ductus cirri or on everted cirri. Distal part of vas deference coiled forming two to four loops; looped region covered by loose, poorly stained cell layer; external seminal vesicle absent. Ovary median, large, 617–1015 (n=2) wide and 714–1010 (n=2) long, flabelliform, with several long lobules pointing mainly posteriorly; prominent unbranched antero-poral lobe extends anterior to vitellarium, sometimes overlapping Mehlis’ gland.Vitellarium poral, elongate, 265–480 (n=2) wide and 214–280 (n=2) long, slightly curved, usually bilobed, median end reaching near midline of proglottid. Mehlis’ gland spherical or ovoid, positioned anterior to middle part of vitellarium. Longitudinal axis of vitellarium inclined posteriorly with respect to longitudinal axis of proglottid. Vagina 430-500 (n=2) long and 25-30 (n=2) wide, distinctly longer than cirrus sac, of uniform width, slightly curved, opening posterior or postero-ventral to cirrus sac. Seminal receptacle ovoid, 107–320 (n=3) in larger diameter. Uterus appears initially as wide, transverse band or tube anterior to ovary, with few narrow branches pointing postero-laterally. Fully developed uterus consisting of short anterior trunk with distinct anterior appendage, one to three primary branches and several long secondary branches pointing posteriorly and postero-laterally; branches disintegrate partly in terminal gravid proglottids. Eggs small, with delicate wall, evidently ovoid or elongate (shape of unfixed eggs and embryophores unknown). Remarks. Meggittina numida is morphologically indistinguishable from the type material of S. oranensis (Joyeux & Foley 1930) (Fig. 4), and therefore the synonymy suggested by Haukisalmi et al. (2018) is confirmed here. Skrjabinotaenia oranensis of Joyeux et al. (1951), Wolfgang (1956) and Elmahy (2022) is shown here to be actually S. psammomi, a species assigned to a new genus as its type and only species (below). Skrjabinotaenia oranensis is a parasite of gerbils (Muridae: Gerbillinae) in North Africa (Algeria, Tunisia).