A comparative assessment of the morphology ofProfilicollis altmani(Acanthocephala, Polymorphidae) from crustaceans and shore birds in Peru, with special notes on hook elemental analysis (EDXA), SEM imaging, histopathology, and molecular profile

Abstract

The morphology of cystacanths and adults of Profilicollis altmani (Perry, 1942) Van Cleave, 1947 (Polymorphidae) were studied from the Pacific mole crab Emerita analoga (Stimpson) (Crustacea, Hippidae) and Belcher’s gull Larus belcheri (Vigors) (Aves, Laridae), respectively, in Peru. Comparative morphometrics with accounts of other populations of P. altmani from elsewhere off the Pacific and Atlantic coasts of North and South America revealed marked intraspecific population variations. We report scanning electron micrographs (SEM) of new features, not before noted or captured in line drawings by earlier observers. We further present microscope images that reveal internal details not previously reported or possible to see with SEM. Energy dispersive X-ray analysis (EDXA) revealed unusual patterns in the chemistry of proboscis hooks especially the high sulfur and diminished phosphorous and calcium in hook tips and low sulfur and high levels of phosphorous and calcium at mid hooks. The size and shape of all hooks of the cystacanths are reported for the first time. Histopathological studies in L. belcheri from Peru are also included. Cystacanths of P. altmani from California were also analyzed for molecular patterns and compared with other sequences reported from other locations. The molecular data and the analysis of our new sequences of cytochrome oxidase I (COI) showed that haplotypes of P. altmani had low genetic variation; the species is not geographically structured, and within its clade no monophyletic group is formed.

Review of the concept of Profilicollis Meyer, 1931 with a description of Profilicollis rancoensis n. sp. (Acanthocephala: Polymorphidae) from the freshwater crab, Aegla abtao Schmitt, 1942 (Decapoda: Anomura) in Chile, with a key to congeneric species

“…is highly divergent from other species of Profilicollis included in the analysis (COI = 14% and 18S = 21% from P. botulus ). These results are similar to those for the genus Profilicollis previously reported [ 9 , 18 , 54 , 56 ], showing the influence of environmental variables on a specific host-parasite relationships, as well as that mobility of hosts is determinant in the strict parasite-intermediate host links [ 25 , 41 , 54 , 56 ]. Regarding host habitat, environmental conditions may limit acanthocephalan species to particular crab hosts that are exposed to different habitats [ 41 , 56 , 67 ].…”

“…in India, had characteristically very low levels of phosphorus, sulfur, and calcium in anterior, middle, and posterior hooks alike [ 10 ]. A detailed discussion of the biological significance of EDXA as a diagnostic tool is exemplified by the observation that populations of an acanthocephalan species will consistently have similar EDX analysis irrespective of host species or geography, even though comparative morphometrics of different populations of the same species usually vary with host species and geography, as presented in Amin et al [ 9 , 10 ].…”

“…In general, there are several taxa in Polymorphidae that do not form monophyletic groups, such the genus Profilicollis [ 6 , 9 , 41 , 54 , 56 ]. These results indicate that the systematic positions of the Acanthocephala are still unstable, and the composition of the genera need to be revised.…”

Morphological and molecular updates of Corynosoma bullosum (Linstow, 1892) Raulliet & Henry, 1907 parasitizing southern elephant seals from the Antarctic Peninsula

“…However, this species appears as sister species to Andracantha sigma, with a relatively low genetic divergence (10%). In the family Polymorphidae, low genetic diversity has been estimated within species of the genera Andracantha, Corynosoma, Pro licollis, and Tenuisoma [7,18,19,20,21,22]. The same is valid for members of Archiacanthocephala class [23,24].…”

New perspectives on morphological and genetic variability of Corynosoma bullosum [Linstow, 1892] parasitizing southern elephant seals from the Antarctic Peninsula

“…Most studies have suggested that the classification of the Phylum Acanthocephala based only on morphological characters shows instability due to the conservative and simple morphology of the group (García-Varela & Pérez-Ponce de León 2008;Presswell et al 2018;Amin et al 2019Amin et al , 2022Presswell et al 2020). Therefore, we are assuming that the combination of molecular and morphological tools is a proper approach to resolving taxonomic ambiguities.…”