New morphological and molecular perspectives aboutMacracanthorhynchus hirudinaceus(Acanthocephala: Oligacanthorhynchidae) from wild boar,Sus scrofaLinn., in Ukraine

Abstract

We make new morphological observations not previously reported for the old acanthocephalan Macracanthorhynchus hirudinaceus (Pallas, 1781) Travassos, 1917, described for the first time about 240 years ago. Our specimens were collected from the wild boar, Sus scrofa Linn., in Ukraine in 2005. We provide comparative morphometrics with other populations from Ukraine, Union of Soviet Socialist Republics, Europe, Brazil and the United States of America. Our specimens from the Ukraine had the smallest trunk (110–120 mm long), longest and thickest hooks, with the third hook being the largest, largest eggs, and a proboscis wider than long. We document the morphology of the proboscis, apical organ, hooks, hook roots, sensory pores, micropores, and eggs with scanning electron microscopy for the first time. We also provide chemical analysis of hooks and eggs using energy-dispersive X-ray analysis, discuss its micropores, and provide a new molecular profile based on 18S rDNA from a European population for the first time. Edge of hook tips feature high levels of calcium and phosphorous but the high level of sulphur is mostly found in the cortical layer of eggs. One new partial 18S rDNA sequence (482 nt length) was generated from an adult specimen of M. hirudinaceus. We present the first 18S rDNA published sequence for this cosmopolitan acanthocephalan obtained from Europe. The amplified region corresponded to the approximate middle region of the small subunit ribosomal ribonucleic acid gene, which is ~1800 nt in length. This molecular contribution is especially valuable in light of the extreme scarcity of genetic information about species of Macracanthorhynchus and of the family Oligacanthorhynchidae as a whole.

Epidemiology and Integrative Taxonomy of Helminths of Invasive Wild Boars, Brazil

“…The morphometric data of M. hirudinaceus in this study were compared to those of Lisitsyna [ 27 ] (2019) and Amin et al [ 28 ] (2021) and presented in Table S7 . Photomicrographs of taxonomic interest are presented in Figure S8 .…”

“…This study provides detailed morphologic and morphometric data of the recovered helminth species; there are a few studies about this topic, such as the reports of Dakova and Panayotova-Pencheva [ 19 ] on A. strongylina and O. dentatum from wild boars in Bulgaria; Giang et al [ 21 ] on S. ransomi from pigs in Vietnam; Pinheiro et al [ 24 ] on G. urosubulatus from domestic pigs in Brazil; and Lisitsyna [ 27 ] and Amin et al [ 28 ] on M. hirudinaceus from wild boars in Ukraine. Nevertheless, the current analyses in this regard for most of them are few and outdated; this is especially true for S. dentatus , as anatomic studies on this species are scarce and dated [ 42 , 43 , 44 ]; for T. suis , as there is no clear differential criterion from Trichuris trichiura and new morphological criteria are needed to differentiate these two species [ 25 ]; and for M. hirudinaceus , as this species appears to exhibit considerable size variation of taxonomically important structures in relation to geographic region and host [ 28 ]. The intraspecific variation in the morphometric characteristics of the various helminth species found in relation to previous studies may be due to differences in methods of preparing and observing the specimens, as well as to peculiarities of the parasite and host populations distributed worldwide [ 19 ].…”