Scaphiostomum undetermined
Creators: name: Panti-May, Jesús Alonso
name: Moguel-Chin, Wilson Isaias
name: Hernández-Mena, David Iván
name: Cárdenas-Vargas, Miguel Humberto
name: Torres-Castro, Marco
name: García-Prieto, Luis
name: Digiani, Maria Celina
name: Hernández-Betancourt, Silvia F.
name: Vidal-Martínez, Víctor Manuel
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Platyhelminthes
Trematoda
Diplostomida
Brachylaimidae
Scaphiostomum
Scaphiostomum undetermined

description: Scaphiostomum sp.
Site of infection: Small intestine
Host species: Heteromys gaumeri and Sigmodon toltecus
Localities: Hobonil ranch, Santa Cruz cattle ranch (Yucatan) and Zoh Laguna community (Campeche)
Specimens deposited: CNHE 10973, 11954‒6
GenBank accession number: OR271636
Comments: The collected specimens have morphological features that allowed us to identify them as a species of the genus Scaphiostomum (Mas-Coma et al. 1986), i.e., body filiform with tegument unspined; suckers slightly spaced; pharynx small; testes and ovary in tandem (ovary inter-testicular), close to each other, inter-caecal; cirrus-sac small; genital pore anterior to anterior testis; vitellarium not reaching at the level of ventral sucker and terminating posteriorly at level of anterior testis; uterus very long, forming numerous loosely arranged coils, anteriorly very close to ventral sucker. Our specimens had suckers nearly equal in size; prepharynx absent; esophagus absent; anterior testis bilobed; and vitellarium slightly separated from the posterior region of the ventral sucker (Figure 2A). The main measurements of our specimens were: body length 5250‒9625, maximum width 912.5‒1225; oral sucker 262.5‒375 long by 250‒375 wide; ventral sucker 250‒312.5 long by 237.5‒325 wide; eggs 29.5‒31.5 long by 19.5‒20 wide. Two species of Scaphiostomum have been reported in American rodents (Mas-Coma et al. 1986), Scaphiostomum microti (Kruidenier & Gallicchio) and Scaphiostomum pancreaticum Mclntosh. However, these species can be differentiated from our specimens by having a longer body (9710‒12750 in Sc. pancreaticum), smaller oral sucker (128‒220 in Sc. microti and 235 in Sc. pancreaticum), ventral sucker (150‒220 in Sc. microti and 240 Sc. pancreaticum), and larger eggs (32‒38 in Sc. microti and 35 in Sc. pancreaticum). In Belize, Bersot (2001) reported Sc. pancreaticum in H. gaumeri and O. phyllotis, however, he also stated that the identity of this trematode should be confirmed. Considering that the brief morphological description of Bersot´ (2001) specimens is closer to our specimens than that of Sc. pancreaticum, it is likely that the trematode from the Yucatan Peninsula represent a new, undescribed Scaphiostomum species.
This is the first record of the genus Scaphiostomum in Mexico and for S. toltecus.
description: Published as part of 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, pp. 205-240 in Zootaxa 5357 (2) on pages 209-210, DOI: 10.11646/zootaxa.5357.2.3, http://zenodo.org/record/10017978