Hobergia, Gardner & Dursahinhan & Campbell & Rácz, 2020

Gardner, Scott L., Dursahinhan, Altangerel T., Campbell, Mariel L. & Rácz, S. Elizabeth, 2020, A new genus and two new species of unarmed hymenolepidid cestodes (Cestoda Hymenolepididae) from geomyid rodents in Mexico and Costa Rica, Zootaxa 4766 (2), pp. 358-376 : 364

Hobergia n. gen.

( Figs. 1–6 )

LSIDurn:lsid:zoobank.org:act: 439BC5C8-B0AE-4108-94ED-044B34E1DB9D

Type and only species: Hobergia irazuensis n. gen., n. sp.

Diagnosis: Hymenolepididae , Hymenolepidinae. Strobila elongate, widest at level just anterior to terminal gravid proglottids. Strobila attenuated and narrowest in neck region, posteriad to scolex. Scolex with four fully developed and separate suckers ( Fig. 1 ). Each sucker with foveola and associated structures. Foveolae completely contain suckers when suckers are retracted ( Fig. 2 ). Apical organ, piriform ( Fig. 1 ). Anterior most part of osmoregulatory canals not penetrating apical organ sac. Transverse tubes connect ventral osmoregulatory canals. Genital ducts pass dorsal to osmoregulatory canals. Genital pores dextral, marginal, and unilateral. Cirrus sac, internal seminal vesicle, and external seminal vesicle dorsal to seminal receptacle, ovary, vitelline gland, and Mehlis’ gland. Vitelline and Mehlis’ glands posterior and slightly ventral to divided ovary. Two laterally extended lobes of ovary, connected by narrow isthmus, clearly lie on each side of vitelline gland. Gravid proglottids with transverse saccular uterus. Terminology of egg morphology follows Ubelaker (1980). Eggs ( Fig. 6 ) subspherical, embryophore larvae with three pairs of hooks, including: 1 st pair dimorphic consisting of 1 small and 1 large hook, 2 nd (middle pair) monomorphic delicate, 3 rd pair dimorphic consisting of 1 small and 1 large hook. Large embryo hooks have a wide and thick guard compared to the small embryo hooks of both the middle pair and the paired small-hooks of 1 st and 3 rd pairs. Middle pair of embryo hooks identical, with falcate blade having shallow curve and with most delicate and narrow guard of all three embryo hook types ( Fig. 6 ).

Etymology: The new genus is named in honor of Dr. Eric P. Hoberg who was the last curator of the United States National Parasite Collection. We honor Eric’s life-long dedication and acknowledge his tireless studies of the taxonomy, systematics, phylogenetics, historical ecology, and biodiversity of parasites of planet earth.

Remarks: Definition of a new structure in the Cestoda. Scolex with pockets or depressions = foveolae (see definition in Maggenti et al., 2009) into which suckers can be retracted. This structure has also been observed in tapeworms of the genus Linstowia Zschokke, 1899 ( Cestoda: Anoplocephalidae ) from marsupials and monotremes ( Gardner & Campbell, 1992 a, b).

Figures

FIGURE 1. Scolex of Hobergia irazuensis n. gen., n. sp. showing details of apical organ and apical organ sac. Line indicates apical organ sac.

FIGURE 2. Scolex of Hobergia irazuensis n. gen., n. sp. showing detail of membranes on the scolex that cover the suckers creating a foveola or pocket into which each sucker can be retracted. Line indicates pocket opening.

FIGURE 3. Image of distal end of cirrus sac of Hobergia irazuensis n. gen., n. sp. showing the spinose nature of the cirrus (line).

FIGURE 4. Line drawing of last mature proglottid of Hobergia irazuensis n. gen., n. sp.

FIGURE 5. Image of terminal gravid proglottids of Hobergia irazuensis n. gen., n. sp. showing the uterus filled completely with eggs in the subterminal proglottid and the terminal segment with no eggs evident (anapolytic).

FIGURE 6. Egg of H. irazuensis n. gen., n. sp. showing extent of development of embryo hooks with usual dimorphic hooks of the lateral pairs and the monomorphic hooks of the central pair in the embryophore larva.