Ahamulina, Marques, Fernando P. L., Jensen, Kirsten & Caira, Janine N., 2012

Marques, Fernando P. L., Jensen, Kirsten & Caira, Janine N., 2012, Ahamulina n. gen. (Cestoda: Diphyllidea) from the polkadot catshark, Scyliorhinus besnardi (Carcharhiniformes: Scyliorhinidae), off Brazil, Zootaxa 3352, pp. 51-59 : 53

Ahamulina n. gen.

Type species: Ahamulina catarina n. sp.

Etymology: Ahamulina (hamulus, L., diminutive, hooks) refers to the absence of lateral hooklets in members of this genus.

Diagnosis: Scolex with 1 dorsal and 1 ventral bothrium, armed apical organ, and cephalic peduncle. Bothria free posteriorly for much of their length, with trifurcate spinitriches on proximal and distal surfaces. Apical organ bearing 1 dorsal and 1 ventral group of hooks; hooks in each group solid, arranged in single, irregular row; adjacent hooks not articulating with one another; lateral hooklets absent. Cephalic peduncle short, unarmed, craspedote. Worms apolytic. Common genital pore mid-ventral. Cirrus sac bipartite, consisting of spherical proximal portion and tubular distal portion, containing coiled cirrus; cirrus with spinitriches. Vagina opening posterior to cirrus sac at common genital pore. Ovary inverted-A shaped in frontal view, bilobed in cross-section. Vitellarium follicular; vitelline follicles circumcortical, anterior to ovary. Uterus saccate, ventral; uterine duct extensive, sinuous, entering in posterior third of uterus. Eggs in gravid proglottids unembryonated. Parasites of Scyliorhinidae III sensu Naylor et al. (2012).

Remarks: Ahamulina n. gen. differs from Ditrachybothridium in its possession, rather than lack, of apical organ hooks. Furthermore, the apical organ of this new genus is prominent, rather than feebly developed. The apical hooks of Ahamulina n. gen. are unlike those of Echinobothrium species in that they are solid, rather than hollow, do not articulate with one another, and the dorsal and ventral groups of hooks are each arranged in a single, rather than a double, row and thus, the distinction between type A and B hooks seen in species of Echinobothrium is not seen in Ahamulina n. gen. Furthermore, lateral hooklets flanking the dorsal and ventral groups of hooks in most of Echinobothrium species are lacking entirely. The absence of cephalic peduncle spines, while unusual, is not unique, given that these spines are also lacking in several species of Echinobothrium (e.g., E. benedeni Ruszkowski, 1927 , E. euterpes [ Neifar, Tyler & Euzet, 2001] Tyler, 2006; E. reesae Ramadevi, 1969 ; E. rhynchobati [ Khalil & Abdul-Salam, 1989] Tyler, 2006; E. sinense [ Li & Wang, 2007] Kuchta & Caira, 2010; E. syrtense [ Neifar, Tyler & Euzet, 2001] Tyler, 2006) and also in both species of Ditrachybothridium . The bipartite nature of the cirrus sac seen in this new genus is also unique among diphyllideans. Ahamulina n. gen. differs further from all of the diphyllideans that have been examined with scanning electron microscopy in that all surfaces of the scolex lack palmate and/or pectinate spinitriches or spines; instead trifurcate spinitriches are present on both the proximal and distal bothrial surfaces. It should be noted that, although Tyler (2006) referred to the spinitriches seen in D. macrocephalum as pectinate, based on the formalized new microthrix terminology proposed by Chervy (2009), the form he illustrated (fig. 21D) would more appropriately be considered to be trifurcate.