Two new species of Acanthobothrium Blanchard, 1848 (Cestoda, Onchoproteocephalidea) from Urobatisjamaicensis (Cuvier, 1816) (Elasmobranchii, Batoidea, Myliobatiformes) of the Mexican Caribbean

Eight specimens of Urobatisjamaicensis were collected from four localities of the Yucatan Peninsula, Mexico, of which four specimens were infected with cestodes of two new species of Acanthobothrium. Acanthobothriumgarciaprietoisp. nov. differs from congeners by a combination of characters including the size of the scolex and bothridia, length of the cephalic peduncle, length of the axial and abaxial prongs and total length of the abaxial prongs of the hooks, size of the cirrus sac and testes in mature proglottids, and the total number of proglottids. The most prominent characteristic distinguishing A.pulidofloresaesp. nov. from other species of the Atlantic Ocean/Caribbean Sea/Gulf of Mexico is the form of the scolex, which has the "clover leaf" configuration. In addition, it can be distinguished by the total length of the worm, total number of proglottids, small accessory suckers, the form of the bothridia, length of the axial and abaxial prongs and total abaxial prong length of hooks, and the number of testes. According to the current category scheme, A.garciaprietoisp. nov. and A.pulidofloresaesp. nov., belong to categories 1 and 5, respectively.

What's in a name? Taxonomic and gender biases in the etymology of new species names

As our inventory of Earth's biodiversity progresses, the number of species given a Latin binomial name is also growing. While the coining of species names is bound by rules, the sources of inspiration used by taxonomists are an eclectic mix. We investigated naming trends for nearly 2900 new species of parasitic helminths described in the past two decades. Our analysis indicates that the likelihood of new species being given names that convey some information about them (name derived from morphology, host or locality of origin) or not (named after an eminent scientist, or for something else) depends on the higher taxonomic group to which the parasite or its host belongs. We also found a consistent gender bias among species named after eminent scientists, with male scientists being immortalized disproportionately more frequently than female scientists. Finally, we found that the tendency for taxonomists to name new species after a family member or close friend has increased over the past 20 years. We end by offering suggestions for future species naming, aimed at honouring the scientific community's diversity and avoiding etymological nepotism and cronyism, while still allowing for creativity in crafting new Latin species names.

Threatened, host-specific affiliates of a red-listed host: Three new species of Acanthobothrium van Beneden, 1849 (Cestoda: Onchoproteocephalidea) from the endangered white skate, Rostroraja alba (Lacépède)

The white skate, Rostroraja alba (Lacépède), is listed as an endangered species, the second-highest category before being declared extinct in the wild, in the International Union for Conservation of Nature's (IUCN) Red List of Threatened Species. This species is heavily affected by anthropogenic impacts such as capture induced stress by overfishing and by-catch, habitat degradation and pollution that caused a drastic decline in populations in recent years. As part of a larger study on elasmobranch affiliates in southern Africa, two specimens of R. alba were screened. Three species of the tapeworm genus Acanthobothrium van Beneden, 1849 (Cestoda: Onchoproteocephalidea) were discovered. Application of Ghoshroy and Caira's classification system facilitated the differentiation of congeners through a combination of specific morphological characteristics. As a consequence, three species new to science are described herein, namely Acanthobothrium umbungus n. sp., Acanthobothrium usengozinius n. sp., and Acanthobothrium ulondolozus n. sp. In light of these new discoveries from an endangered host, it is apparent to address the conservation status of its affiliate species, that co-evolved with their elasmobranch hosts for millions of years, thereby creating unique and intimate host-parasite interrelationships. Currently, altering environmental conditions caused by anthropogenic pressures have direct impacts on this host-parasite system with increasing risks of extinction. As merely 9% of elasmobranchs in South African waters have been examined for endohelminths and other affiliate taxa, extensive studies on these organisms and their hosts implementing multisource approaches are needed. This will provide a better understanding on the intimate nature of host-parasite systems that may lead to new prospects in conservation science and the preservation of threatened host species, such as R. alba, together with their unique fauna of affiliate species.

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Three new species of Acanthobothrium were discovered in the endangered white skate, Rostroraja alba, off the coast of South Africa.

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The three species described (A. umbungus n. sp., A. usengozinius n. sp., and A. ulondolozus n. sp.) display merely a single cestode genus among the hidden diversity of species from elasmobranchs.

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The current increase in threatened free-living host species results in an even greater loss in affiliate species that remain unknown and scientifically underexplored.

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Assessing the status and incorporating affiliate species (i.e. cestodes) into novel conservation schemes may contribute to the conservation of threatened host species and marine populations worldwide, which, in turn, will protect affiliate species as vital “key players” for host species and entire ecosystems.

Four new species of Acanthobothrium van Beneden, 1849 (Cestoda: Onchoproteocephalidea) from the spotted skate, Raja straeleni Poll, off the Western Cape, South Africa

The examination of eight spotted skates, Raja straeleni Poll, resulted in the discovery of four new species of Acanthobothrium van Beneden, 1849, namely A. microhabentes sp. n., A. microtenuis sp. n., A. crassus sp. n., and A. dolichocollum sp. n., located off the Western Cape of South Africa. With a total of over 200 valid species of Acanthobothrium recognised worldwide, the use of an integrative approach becomes imperative in the interest of simplifying interspecific comparisons between congeners. In accordance with this, the four new species were incorporated into the category classification system established by Ghoshroy and Caira in 2001, where they were identified as category 2 species, which, at present, includes 47 recognised species of Acanthobothrium. Nevertheless, each of the four new species exhibits postovarian testes, a most intriguing and highly unusual feature among Acanthobothrium, instantly differentiating them from most congeners. This feature has been reported in 12 congeners, which have previously been considered to be restricted to waters of the Indo-Pacific Ocean. Not only do the four new congeners represent the first species of Acanthobothrium reported from southern Africa, but they also represent the first reported species with postovarian testes from the southern Atlantic Ocean. Regarding the legitimacy of the four new species, only two other category 2 species are reported to exhibit this feature, namely A. popi Fyler, Caira et Jensen, 2009, and A. bobconniorum Fyler et Caira, 2010, to which the four congeners were compared to. Acanthobothrium microhabentes sp. n. is the smallest of the congeners and differs from A. popi and A. bobconniorum by having fewer testes and postovarian testes, a shorter body, fewer proglottids, a shorter scolex, and longer cephalic peduncle. Acanthobothrium microtenuis sp. n. differs from A. popi and A. bobconniorum by having fewer testes and postovarian testes, a shorter scolex, longer cephalic peduncle, and the possession of columnar spinitriches on the anterior region of the terminal proglottid. Acanthobothrium crassus sp.n. differs from A. popi and A. bobconniorum by having fewer postovarian testes, a narrower cirrus-sac, larger vitelline follicles, and a longer cephalic peduncle. Acanthobothrium dolichocollum sp. n. is the longest of the four new species and differs from A. popi and A. bobconniorum by having fewer postovarian testes, more postporal testes, a larger body, more proglottids, larger testes and vitelline follicles, and an exceptionally long cephalic peduncle. Apart from differences in overall size, the four new species differ in a combination of measurements for the scolex, vitelline follicles, muscular pad and cephalic peduncle, and the number of proglottids and testes. The four species were recovered from a previously unexplored host and locality, expanding the host associations and geographical distribution of the genus.

Two new species of Acanthobothrium Blanchard, 1848 (Cestoda: Onchoproteocephalidea) from rajiform batoids off Argentina

Two new species of Acanthobothrium Blanchard, 1848 were collected from rajiform batoids along the coast of Argentina. They are Acanthobothrium carolinae sp. n. from Bathyraja magellanica (Philippi) and Acanthobothrium domingae sp. n. from Dipturus brevicaudatus (Marini). Both belong to category 1 and 2 because their total length is lower than 15 mm, they have fewer than 50 proglottids, fewer than 80 testes and a symmetric or asymmetric ovary. Acanthobothrium carolinae sp. n. differs from all congeners by the following combination of features: proglottid apolysis, hook morphology, microthrix pattern on the cephalic peduncle and distribution of the vitelline follicles. Acanthobothrium domingae sp. n. is unique in the combination of proglottid apolysis, total length, number of proglottids, hook and septal morphology, microthrix pattern on the cephalic peduncle, number and distribution of testes, cirrus sac length, distribution of the vitelline follicles and genital pore position. The discovery of these species increases the number of species of Acanthobothrium parasitising rajiform batoids off Argentina from one to three. All three species have a unique pattern of distribution of the gladiate spinitriches along the length of the cephalic peduncle, i.e., gladiate spinitriches being interrupted in a medial line both dorsally and ventrally.

Host relationships and geographic distribution of species of Acanthobothrium Blanchard, 1848 (Onchoproteocephalidea, Onchobothriidae) in elasmobranchs: a metadata analysis

Species of Acanthobothrium have been documented as parasites of the spiral intestine of elasmobranchs. Results of a metadata analysis indicate that 114 species of elasmobranchs have been reported as hosts of 200 species of Acanthobothrium. The metadata analysis revealed that 3.7% of species of sharks and 14.9% of species of rays that have been reported as hosts to date; some species are parasitized by more than one species of Acanthobothrium. This work provides a Category designation, as proposed by Ghoshroy and Caira (2001), for each species of Acanthobothrium. These Category designations are a tool to facilitate comparisons among members of Acanthobothrium for descriptions of new species in the future.

A new species of Alexandercestus Ruhnke and Workman, 2013 (Cestoda: Phyllobothriidea) from the sicklefin lemon shark, Negaprion acutidens (Elasmobranchii: Carcharhinidae), in the Gulf of Oman

A new species, Alexandercestus masoumehae n. sp., is described from the sicklefin lemon shark, Negaprion acutidens (Rüppell), from the Iranian coast of the Gulf of Oman. The new species is the third in this genus, all parasitizing species of Negaprion Whitley. Based on morphological characters and scanning electron microscopy the new species is different from its congeners of in a combination of characters including total length, terminal proglottid length, cirrus sac length, and genital pore position. Compared to Alexandercestus gibsoni Ruhnke & Workman, 2013 and A. manteri Ruhnke & Workman, 2013 the specimens of the new species are smaller (7.08-8.5 mm), with a smaller terminal proglottid length to width ratio (1:0.7-1.3 vs. 1.4-3.2:1 and 1.2-3.1:1, respectively), and have a more anterior genital pore (70-73% of proglottid length vs. 42-66% and 41-65%, respectively). In addition, A. masoumehae possesses less foliose bothridia compared with A. gibsoni, and more densely packed vitelline follicles in comparison with A. manteri. The SEM examination of the scolex in the new species reveals a specific pattern of microtriches adding new details in our understanding of the surface morphology of members of Alexandercestus. Finally, the new species increases the total number of described tapeworm species from N. acutidens to five and the described tapeworms in the Persian Gulf and Gulf of Oman region to 65.