Skrjabinus sp.

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 : 210

Skrjabinus sp.

Site of infection: Bile ducts

Host species: Heteromys gaumeri

Locality: Hobonil ranch (Yucatan)

Specimens deposited: CNHE 11957

GenBank accession number: OR271635

Comments: The morphology observed in the specimens of this study agrees with the characteristics established for the genus Skrjabinus ( Pojmańska 2008) , i.e., body elongate and fusiform, tegument unspined with acetabulum in anterior third of body, larger than the oral sucker; pharynx well developed and esophagus short, intestinal bifurcation anterior to ventral sucker and caeca reaching the posterior region of the hind body. Testes postero-lateral to ventral sucker. Cirrus-sac extends beyond intestinal bifurcation. Genital pore posterior to the pharynx but anterior to intestinal bifurcation. Ovary rounded, submedian, post-testicular, separated from testes by uterine coils. Uterus intercaecal, occupying entire hind body. Vitelline follicles fine, begin from the middle or from the posterior margin of the ventral sucker and reach the final region of the second third of the body. The main measurements of our specimens were: body length 2825‒3725 and maximum width 875‒1475; oral sucker 300‒350 long by 275‒362.5 wide; pharynx 125‒162.5 long by 137.5‒175 wide; ventral sucker 425‒537.5 long by 437.5‒500 wide; oral sucker/ ventral sucker ratio 1.3‒1.8; and eggs 32.5‒37.5 long by 20‒22.5 wide. The most similar species to our specimens is Skrjabinus delectans (Braun) , parasite of Nothura maculosa (Temminck) from Argentina; however, Sk. delectans exhibits some morphological differences ( Sutton & Lunaschi 1987), such as a shorter oral sucker (vs 160‒200), shorter pharynx (vs 60‒80), lower oral sucker/ventral sucker ratio (vs 1.6‒2.8) and vitellarium not distributed to the last posterior third of the body ( Figure 2B and C ). For this reason, we consider that our specimens may represent a species not described yet.

This is the first record of the genus Skrjabinus in Mexico and for H. gaumeri .

Figures

FIGURE 2. A.Adult specimen of Scaphiostomum sp. from Heteromys gaumeri, ventral view. B. Adult specimen of Skrjabinus sp. from Heteromys gaumeri, ventral view. C. SEM micrograph of Skrjabinus sp. from Heteromys gaumeri showing the ventral surface and the acetabulum, ventral view. D. Adult specimen of Microphallidae gen. sp. from Peromyscus yucatanicus, ventral view.