Heligmonellidae, Skrjabin & Schikobalova

Panti-May, Jesús Alonso, Moguel-Chin, Wilson Isaias, Hernández-Mena, David Iván, Cárdenas-Vargas, Miguel Humberto, Torres-Castro, Marco, García-Prieto, Luis, Digiani, Maria Celina, Hernández-Betancourt, Silvia F. & Vidal-Martínez, Víctor Manuel, 2023, Helminths of small rodents (Heteromyidae and Cricetidae) in the Yucatan Peninsula, Mexico: an integrative taxonomic approach to their inventory, Zootaxa 5357 (2), pp. 205-240 : 221

Heligmonellidae gen. sp.

Site of infection: Mesentery

Host species: Sigmodon toltecus

Localities: Vallazoo (Yucatan)

Specimens deposited: CNHE 12023

GenBank accession numbers: OR271670

Comments: Only two female specimens were collected from the mesentery of S. toltecus . They exhibited characteristics of the family Heligmonellidae , such as presence of cephalic vesicle; monodelphy, and absence of caudal spine. However, the synlophe was absent ( Figure 4L ). Among heligmonellid nematodes of rodents, a strong reduction or even absence of synlophe is observed in species of the genus Hypocristata Durette-Desset. Three species of this genus have been described from sigmodontine rodents in Northern South America, including Sigmodon hirsutus (Burmeister) (originally described as S. hispidus ) in Venezuela ( Durette-Desset 1971; Durette-Desset & Guerrero 2006). The present specimens are very probably related to Hypocristata but the scarcity and condition of specimens and especially the lack of males prevent a more accurate identification.

Figures

FIGURE 4. A. Posterior end of male specimen of Trichuris silviae from Heteromys gaumeri showing the slightly campanulate spicular sheath (arrow), lateral view. B. SEM micrograph of the anterior extremity of Monodontus sp. from Sigmodon toltecus showing the mouth opening, paired cutting plates and cervical papillae (arrow), ventral view. C. Cross section at midbody showing features of the synlophe of female Vexillata vexillata from Heteromys gaumeri. D. Male caudal bursa of Vexillata vexillata from Heteromys gaumeri, ventral view. E. Cross section at midbody showing features of the synlophe of male Heligmosomoidea gen. sp. cf. Vexillata from Ototylomys phyllotis. F. Cross section at midbody showing features of the synlophe of female Carolinensis sp. from Peromyscus yucatanicus. G. Cross section at midbody showing features of the synlophe of male Hassalstrongylus aduncus from Sigmodon toltecus. H. Cross section at midbody showing features of the synlophe of female Hassalstrongylus musculi from Oligoryzomys fulvescens. I. Male caudal bursa of Hassalstrongylus musculi from Ototylomys phyllotis, dorsal view. J. SEM micrograph of female Heligmostrongylus sp. from Peromyscus yucatanicus showing the discontinuous ridges, lateral view. K. Male caudal bursa of Heligmostrongylus sp. from Peromyscus yucatanicus, ventral view. L. Cross section at midbody of female Heligmonellidae gen. sp. from Sigmodon toltecus showing the absence of synlophe. Abbreviations: r, right side; v, ventral side. All cross sections of the synlophe orientated as in figure C.