A review of the nematode assemblage of the Australian bandicoot, Isoodon macrourus (Peramelidae), from material held in the South Australian Museum with the description of Sprattellus cassonei n. sp. (Mackerrastrongylidae)

Abstract

A total of 235 vials of nematodes held in the Australian Helminthological Collection of the South Australian Museum from 125 individuals of Isoodon macrourus were examined. The nematode assemblage of I. macrourus, comprising 12 families, including 16 genera and 23 identified species, was compared with the sympatric bandicoot species Perameles nasuta, 20 identified species (Sorensen’s index of similarity 0.56) and P. pallescens, 12 identified species (Sorensen’s index 0.51). Sprattellus cassonei n. sp. is distinguished from its congeners by having a synlophe with 7–8 ridges with the anterior ventral ridges interrupted, the morphology of the dorsal ray and the branching of the spicule tips. A single male specimen identified as Linstowinema sp. 1. is characterised by seven circles of body hooks, the oesophagus terminating at the level of the seventh circle and robust scale-like spines on the posterior ventral body. A complete description of the species will require additional material, including females. Difficulties in identifying individuals of the genus Mackerrastrongylus to species level are discussed. Overall similarities in the nematode assemblages of the three bandicoot hosts are likely due to shared relationships and similar behaviours.

A review and comparison of the nematode assemblages of the Australian golden bandicoot, Isoodon auratus, the quenda, I. fusciventer and southern brown bandicoot, I. obesulus (Peramelidae), from material held in the south Australian museum

“…The specimens from I. obesulus from Tasmania examined for this study also had a shorter spicule (1200) and larger eggs (52–72 by 33–36) than reported by Baylis (1932) for I. macrourus from Queensland. Nevertheless, the suggestion by Mawson (1960) that these differences were not sufficient to erect a new species is supported by data collected by Smales et al (2023a) . They measured seven males and four females from I. macrourus from Queensland (AHC 33184, 33190, 44924, 44927, 44928), obtaining spicule lengths of 1120–1900 and egg sizes of 47 by 30.…”

“…Sorensen's indices of similarity between I. fusciventer and I. macrourus, I. fusciventer and I. obesulus and I. obesulus and I. macrourus (data for I. macrourus from Smales et al, 2023a ), calculated using the fully identified species, were 17.1 %, 27.2 %, and 39.0 % respectively, indicating that the species composition of the three nematode communities were not similar, less than half the species being shared. The nematode community of I. fusciventer showed few similarities with that of either I. obesulus or I. macrourus.…”

“…Nematodes from I. macrourus collected in Queensland, incorrectly registered as from I. obesulus, and not reported in Smales et al (2023a) are listed in Supplementary Table 1 . Of these, only Strongyloides thylacis and Marsupostrongylus bronchialis had not been reported previously from the SAMA AHC collection ( Smales et al, 2023a ).…”

“…There were no records for I. peninsulae (see Spratt and Beveridge, 2016 ) and nothing is presently known about its helminth parasites. The nematode assemblage of I. macrourus was recently reviewed by Smales et al (2023a) . Most of the specimens relating to these records are held in the Australian Helminthological Collection (AHC) of the South Australian Museum (SAMA) with the museum holding material from I. auratus , I. fusciventer as I. obesulus, I. fusciventer and I. obesulus as well as material from I. macrourus, some of which was labelled as from I. obesulus .…”

“…The aims of this project were to re-examine all the nematode material available in the AHC from I. auratus, I. fusciventer and I. obesulus, including its subspecies, to confirm, correct or provide identifications (to at least genus), for each lot. The geographic distribution of each nematode species was confirmed, the composition of the nematode community of each of the three bandicoot species was determined and comparisons were made between the communities of I. fusciventer, I. macrourus (see Smales et al, 2023a ) and I. obesulus, as well as between the communities of the subspecies of I. obesulus, namely Isoodon obesulus affinis, I. o. nauticus, and I. o. obesulus.…”