Gerbillitaenia psammomi Haukisalmi & Elmahy 2025, n. comb.
Creators: name: Haukisalmi, Voitto
name: Elmahy, Rasha A.
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Platyhelminthes
Cestoda
Cyclophyllidea
Catenotaeniidae
Gerbillitaenia
Gerbillitaenia psammomi

description: Gerbillitaenia psammomi (Mikhail & Fahmy, 1968) n. comb.
(Figs. 2, 7, 8; Table 3)
Synonym: Skrjabinotaenia psammomi Mikhail & Fahmy, 1968.
No type specimens were designated for G. psammomi.
Material examined: Three specimens from Psammomys obesus from Egypt (see Elmahi 2012; Elmahy 2022), and four specimens from Meriones shawi from Morocco (MHNG 44899), described and identified by Joyeux et al. (1951) as S. oranensis.
Deposited voucher specimens (slides): FMNH: KN.47858, KN.47859 from P. obesus.
Description: The present description is based on three pregravid specimens from P. obesus. The measurements and counts provided by Elmahi (2012) and Elmahy (2022) are shown in Table 3.
Strobila longitudinally elongate, length of two pregravid specimens 29–30 mm; maximum width 2.6–4.1 mm, attained at premature proglottids. Number of proglottids 8–10. Anterior end of strobila blunt, widening rapidly. Margins between proglottids first convex, then becoming slightly concave. Dimensions of mature proglottids (n=4): length 1.5–2.2 mm, width 2.5–4.0 mm and length/width ratio 0.55–0.60; dimensions of pregravid/gravid proglottids (n=4): length 5.7–7.6 mm, width 2.1–2.8 mm and length/width ratio 2.4–2.7. Scolex not distinctly separate from neck region. Suckers 240–350 (n=11) in diameter. Osmoregulatory system consists of multiple narrow, anastomosing longitudinal canals. Genital pores regularly alternating, positioned near anterior margin of proglottid; genital atrium indistinct.
Testes 433–438 (n=5) in total number, appearing as two wide lateral groups; number of antiporal testes 233–248 (n=5) and poral testes 190–200 (n=5). Cirrus sac slender, 340–519 (n=5) long and 75–105 (n=5) wide, poorly delimited from vas deferens. Ductus cirri densely lined with fine spines throughout its length. Distal part of vas deferens sometimes slightly coiled. Distinct Internal and external seminal vesicles absent.
Ovary median or slightly poral, with numerous lobules pointing laterally and posteriorly and few anteriorly, antero-poral lobe absent; length and width of ovary 1.1–1.8 mm (n=5) and 0.8–1.5 mm (n=5), respectively.Vitellarium poral, more or less transversely elongate, usually slightly curved, but not distinctly bilobed; width 360–800 (n=5) and length 330–600 (n=5). Longitudinal axis of vitellarium inclined slightly anteriorly with respect to longitudinal axis of proglottid. Vagina long (770–1350, n=5) and slender, of uniform width (30–40, n=5), 2.2–3.8 times longer than cirrus sac, opening postero-ventral to cirrus sac. Inside of vagina densely lined with fine hairs. Distinct elongate seminal receptacle present; length 190–240 (n=5). Spherical Mehlis’ gland positioned anterior to median part of vitellarium. Fully developed (pregravid) uterus with relatively long trunk and 7–8 (n=8) slightly furcating primary branches on each side pointing laterally and postero-laterally; posterior branches forming prominent fan-like group without distinct trunk.
Remarks. In addition to the type material, G. psammomi has been previously described from the type host (P. obesus) from the type region (Egypt) (Elmahi 2012) and from M. shawi from Morocco (Joyeux et al. 1951). The present study includes a reanalysis of the latter materials, both of which were originally identified as S. oranensis (Table 3). There are no significant qualitative or quantitative morphologic differences between the three collections, except that the number of proglottids is slightly smaller in the specimens from Morocco (5–9) than in those from Egypt (8–17). In the original description (Mikhail & Fahmy 1968), the length of strobila is given as 125–320 mm, but considering the number and length of proglottids in these specimens, these figures are evidently too high (perhaps 12.5–32.0 mm was intended). The body length given in Joyeux et al. (1951) (60–80 mm) is also dubious, because the re-examination of these specimens showed that they are only 15–18 mm long. It should be noticed that the apparently lower number of primary uterine branches recorded in this study (6–9), compared with the previous studies (9–14), is due to the fact the posterior branches forming a fan-shaped group were not counted by us. Considering their substantial overall similarity, we conclude that all three materials represent G. psammomi.
The system of osmoregulatory canals in G. psammomi (as S. oranensis) has been illustrated in Quentin (1971).
description: Published as part of Haukisalmi, Voitto & Elmahy, Rasha A., 2025, Taxonomic review of Skrjabinotaenia Akhumyan, Meggittina Lynsdale and Gerbillitaenia gen. nov. (Cestoda: Catenotaeniidae), parasites of rodents, pp. 185-208 in Zootaxa 5590 (2) on pages 200-204, DOI: 10.11646/zootaxa.5590.2.2, http://zenodo.org/record/14952916