CHARACTERIZATION OF SPERMATOZOON ULTRASTRUCTURE IN TETRAGONOCEPHALUM SP. (CESTODA: LECANICEPHALIDEA: TETRAGONOCEPHALIDAE) FROM THE WHIPRAY, UROGYMNUS ASPERRIMUS 1 (DASYATIDAE: UROGYMNINAE).

The Lecanicephalidea represents one of 11 currently recognized elasmobranch-hosted tapeworm lineages. It is quite speciose, with nearly 100 validly recognized species to date. Yet spermatozoon features have been fully characterized for only a single species; spermatozoon characters for a second species were previously included in a data matrix used to infer phylogenetic relationships among cestode orders, but data are limited and no images were provided. Specimens of Tetragonocephalum sp. were collected from the whipray, Urogymnus asperrimus 1, from the Solomon Sea off the Solomon Islands. The mature spermatozoa of Tetragonocephalum sp. are distinctly different from the other lecanicephalidean species for which spermatozoon ultrastructure has been thoroughly investigated. Tetragonocephalum sp. spermatozoa represent the Type IV (sensu Levron, 2010) morphology possessing a single axoneme, crested bodies, cortical microtubules running parallel to the axoneme, and nucleus, which is helical to the axoneme. Although spermatozoa for both lecanicephalideans examined to date are of the Type IV spermatozoon morphology, they differ in the number of crested bodies and cortical microtubules, the relative size of the spermatozoon-specifically as it relates to the nuclear region-and the presence or absence of the anterior spiral structure. Significant spermatozoon character variation is present across these 2 representatives of 2 lecanicephalidean families, indicating that additional studies of representatives of the other families in the order are needed to better understand the extent of character variation present in the Lecanicephalidea. Overall, spermatozoon ultrastructure is understudied in elasmobranch-hosted tapeworm lineages compared to other vertebrate-hosted tapeworm orders at both the species and family levels.

A Quantitative Analysis of Four Undergraduate Human Anatomy Laboratory Curricula: Approaches, Identified Structures, Concepts, and Thematic Emphases.

Human anatomy is a foundational course thatserves diverse pre-professional health care majors. However, limited information is available on the teaching approaches, content, and thematic emphases of this course at the undergraduate level when compared with that of medical and other graduate schools. Herein, we document and quantitatively evaluate the laboratory curriculum of four undergraduate human anatomy courses in the USA. For each course, we assess the total number of structures (terms requiring identification during an exam), concepts (terms requiring an explanation), and clinical applications. To facilitate further assessments, we also compare the content distribution of each course with that recommended by the American Association of Clinical Anatomists (AACA). Two courses followed a regional approach emphasizing the use of human cadavers, while the other two followed a system-based approach and used plastic models and non-human cadaveric materials (e.g., cats and sheep). The total amount of information presented to students differed significantly among curricula. The majority of terms (65-88%) taught to students referred to the identification of anatomical structures whereas clinical applications were rare (< 1.3%). Courses using a regional approach expected students to learn as much as twice the number of terms than those following a system-based approach. Functions, innervations, origins, and insertions of muscles are only included in the curriculum of the courses following a regional approach. The proportion of terms devoted to each anatomical module in all curricula was significantly different from each other, as well as from that of AACA recommendation. We discuss these differences in the curriculum, the challenges and limitations inherent with each teaching approach, as well as in the teaching materials used among the curricula. These quantitative analyses aim to provide insightful information about the structure of the undergraduate human anatomy laboratory curriculum and may prove useful when redesigning a course.

When proglottids and scoleces conflict: phylogenetic relationships and a family-level classification of the Lecanicephalidea (Platyhelminthes: Cestoda).

This study presents the first comprehensive phylogenetic analysis of the interrelationships of the morphologically diverse elasmobranch-hosted tapeworm order Lecanicephalidea, based on molecular sequence data. With almost half of current generic diversity having been erected or resurrected within the last decade, an apparent conflict between scolex morphology and proglottid anatomy has hampered the assignment of many of these genera to families. Maximum likelihood and Bayesian analyses of two nuclear markers (D1-D3 of lsrDNA and complete ssrDNA) and two mitochondrial markers (partial rrnL and partial cox1) for 61 lecanicephalidean species representing 22 of the 25 valid genera were conducted; new sequence data were generated for 43 species and 11 genera, including three undescribed genera. The monophyly of the order was confirmed in all but the analyses based on cox1 data alone. Sesquipedalapex placed among species of Anteropora and was thus synonymized with the latter genus. Based on analyses of the concatenated dataset, eight major groups emerged which are herein formally recognised at the familial level. Existing family names (i.e., Lecanicephalidae, Polypocephalidae, Tetragonocephalidae, and Cephalobothriidae) are maintained for four of the eight clades, and new families are proposed for the remaining four groups (Aberrapecidae n. fam., Eniochobothriidae n. fam., Paraberrapecidae n. fam., and Zanobatocestidae n. fam.). The four new families and the Tetragonocephalidae are monogeneric, while the Cephalobothriidae, Lecanicephalidae and Polypocephalidae comprise seven, eight and four genera, respectively. As a result of their unusual morphologies, the three genera not included here (i.e., Corrugatocephalum, Healyum and Quadcuspibothrium) are considered incertae sedis within the order until their familial affinities can be examined in more detail. All eight families are newly circumscribed based on morphological features and a key to the families is provided. Aspects of morphological evolution and host associations are discussed in a phylogenetic context for each family and for the order as a whole. Lecanicephalidean genera lacking apical structures were confirmed as the earliest diverging lineages. Proglottid anatomy was determined to be much more conserved and indicative of phylogenetic affinities than scolex morphology. Collectively, the Lecanicephalidea parasitize three of the four orders of Batoidea-their almost exclusive absence from skates (Order Rajiformes) appears to be real; only a few records from sharks exist. At the family level, the breadth of host associations is correlated with taxonomic diversity of the family. The degree to which factors such as intermediate host use or host specificity at any stage in the life-cycle shape these patterns is currently unknown.

Floriparicapitus, a new genus of lecanicephalidean tapeworm (Cestoda) from sawfishes (Pristidae) and guitarfishes (Rhinobatidae) in the Indo-West Pacific.

Floriparicapitus n. gen. (Cestoda: Lecanicephalidea), with Floriparicapitus euzeti n. gen., n. sp. as its type, is erected to house 3 new tapeworm species and 2 known species that are transferred to the new genus, all parasitizing sawfishes and guitarfishes (order Rhinopristiformes) in Indo-Pacific waters. The new genus differs from the 21 valid lecanicephalidean genera in its possession of a large scolex bearing a laterally expanded apical organ in the form of a rugose sheet in combination with a cirrus conspicuously armed with spinitriches and 3 pairs of excretory vessels. It most closely resembles Lecanicephalum, but differs conspicuously in its possession of 3, rather than 1, pair of excretory vessels. Two new species are described from sawfishes: Floriparicapitus euzeti n. sp., from Pristis clavata and Floriparicapitus juliani n. sp. from Pristis pristis, both from Australia. Floriparicapitus plicatilis n. sp. is described from the guitarfish Glaucostegus typus in Australia and the guitarfish Glaucostegus thouin in Malaysian Borneo. Two species formerly assigned to Cephalobothrium are transferred to the new genus; Floriparicapitus variabilis ( Southwell, 1911 ) n. comb. from the sawfish Anoxypristis cuspidata in Sri Lanka and Floriparicapitus rhinobatidis ( Subhapradha, 1955 ) n. comb. from the guitarfish Glaucostegus granulatus in India. The species from guitarfish differ conspicuously from those parasitizing sawfish in their possession of only 4 ( F. plicatilis n. sp.) or 5 (F. rhinobatidis n. comb.) testes per proglottid versus 9 or more in the 3 sawfish-parasitizing species. The latter 3 species differ from one another in scolex width, acetabular size, number of proglottids, and cirrus sac size. As it stands, the new genus appears to be restricted to a subclade of the Rhinopristiformes consisting of the sawfishes and species of Glaucostegus.

Stoibocephalum n. gen. (Cestoda: Lecanicephalidea) from the sharkray, Rhina ancylostoma Bloch & Schneider (Elasmobranchii: Rhinopristiformes), from northern Australia.

A new genus and species of lecanicephalidean cestode, Stoibocephalum arafurense n. gen., n. sp., is described from the sharkray, Rhina ancylostoma Bloch & Schneider, off northern Australia. Stoibocephalum arafurense n. gen., n. sp. is apolytic, and possesses a large, muscular, retractable apical organ, 3 pairs of excretory vessels, and testes in several columns and layers. The presence of 3 pairs of excretory vessels distinguishes this new genus from all other valid lecanicephalidean genera, except Hexacanalis Perrenoud, 1931, from which it can be distinguished based on ovary shape and egg morphology. Stoibocephalum n. gen. most closely resembles Tylocephalum Linton, 1890 but differs from that genus in its ability to completely retract its apical organ into the scolex proper. Scolex microthrix pattern and histological sections of scoleces attached in situ suggest S. arafurense n. gen., n. sp. to attach to the host's intestinal mucosa with apical organ and scolex proper surfaces, rather than just the apical organ surface. This is the third lecanicephalidean species described from the sharkray.

A revision of Hexacanalis Perrenoud, 1931 (Cestoda: Lecanicephalidea) and description of H. folifer n. sp. from the zonetail butterfly ray Gymnura zonura (Bleeker) (Rajiformes: Gymnuridae).

Hexacanalis Perrenoud, 1931 was erected for H. abruptus (Southwell, 1911) Perrenoud, 1931 based on the presence of six excretory vessels, a unique feature among the Lecanicephalidea. The genus has since been considered a junior synonym of Cephalobothrium Shipley & Hornell, 1906 or Lecanicephalum Linton, 1890, or as a genus inquirendum. Based on examination of the syntype series of H. abruptus, this species is redescribed and a lectotype designated. Examination of cestodes from the zonetail butterfly ray Gymnura zonura (Bleeker) from off Indonesian Borneo resulted in the discovery of a second species. Hexacanalis folifer n. sp. is unique among lecanicephalideans in its possession of an ovary that is U-shaped in cross-section and craspedote proglottids with prominent posterior dorso-ventral processes in the form of large lappets. The presence of six excretory vessels, confirmed in both species, supports the validity of Hexacanalis. An additional species, H. pteroplateae (Zaidi & Khan, 1976) n. comb., also from a butterfly ray, G. micrura (Bloch & Schneider) [as Pteroplatea micrura (Bloch & Schneider)], is transferred to this genus from Cephalobothrium Shipley & Hornell, 1906. A revised diagnosis of Hexacanalis is presented. Seven species of this genus remain species inquirendae. Hexacanalis appears to parasitise species of the Gymnuridae van Hasselt; however, specific identifications of the hosts are in need of re-evaluation. A summary of the cestode parasites of the Gymnuridae is presented.