Two-jawed (duognathous) terrestrial leeches in the Haemadipsidae are major pests across their wide geographic range, represented by numerous endemic species in Australia and across many islands in the Indian and Pacific Oceans. However, haemadipsid taxonomy, based largely on externally visible characters, remains in conflict with phylogenetic relationships. We capitalize on the power of microcomputed tomography (μCT), allowing for the first description of an extant soft-bodied species – Chtonobdella tanae sp. n. – using this technology. Several fixation strategies for soft-bodied invertebrates in μCT scanning applications are also evaluated. Expanding on prior work, higher taxonomy of duognathous haemadipsids also was evaluated with phylogenetic analyses of DNA sequence data. Whereas monophyly of duognathous leeches was supported, substantial conflict remained with respect to named genera. Consequently, the genus Chtonobdella was revised to include all duognathous leech species previously distributed in 31, mostly monotypic genera.
Chtonobdella tanae sp. n. holotype (AU81) from Queensland Australia, μCT volumetric video rendering of external and internal features.
Video starts with whole-body (anterior to the right) external feature rendering viewed dorsally, laterally, and then ventrally, followed by whole-body internal feature rendering viewed dorsally, laterally, and then ventrally. Video zooms in on eyespots (green), jaws (magenta), ganglia (yellow), and gastric tissue (grey) viewed dorsally, laterally, and then ventrally. Video moves posteriorly, focusing on male median reproductive tissues (shades of blue), female median reproductive tissues (pink), and testisacs (red) viewed dorsally, laterally, and then ventrally. Video goes to the posterior focusing on intestinal tissue (pale green) viewed dorsally, laterally, and then ventrally. Video then focuses on the auricle cavities (blue), finishing on the dorsal view of whole-body internal feature.
Chtonobdella_tanae_AU81_virtual_dissection.mp4
Chtonobdella tanae sp. n. holotype (AU81) from Queensland Australia, μCT projections.
Specimen fixed in 10% formalin and 70% ethanol for over a decade was refixed with AFA, stained in osmium tetroxide, and then scanned in a GE v|tome|x s240.
Chtonobdella_tanae_AU81_tiff_stacks.zip
Juvenile Macrobdella decora, μCT projections.
Specimens were fixed first with either ethanol (small sized specimen on left), glutaraldehyde (large sized specimen in middle), or AFA (medium sized specimen on right); stained in osmium tetroxide; and then scanned in a GE v|tome|x s240.
Macrobdella_decora_juveniles_LeftEthanol_MiddleGlutaraldehyde_RightAFA_tiff_stacks.zip