A new orthopteran-parasitizing horsehair worm, Acutogordius taiwanensis sp. n., with a redescription of Chordodes formosanus and novel host records from Taiwan (Nematomorpha, Gordiida).

Ming-Chung Chiu,Chin-Gi Huang,Shiuh-Feng Shiao,Wen-Jer Wu

doi:10.3897/zookeys.683.12673

Ming-Chung Chiu, Chin-Gi Huang + Show 2 more

Open Access

https://doi.org/10.3897/zookeys.683.12673

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Journal: ZooKeys	Publication Date: Jul 6, 2017
Citations: 8	License type: CC BY 4.0

Affiliation: National Taiwan University, University of Taipei

Abstract

A description of a new species of horsehair worm, Acutogordius taiwanensis sp. n., a redescription of Chordodes formosanus, and novel host records for the latter are provided. Acutogordius taiwanensis sp. n. is morphologically similar to A. protectus with moderately flat areoles on its tail tips, but is distinguishable by small mid-body ornamentations. Despite the distinct differences in the post-cloacal crescents between 14 male samples, their conspecific status, along with that of nine female samples, was upheld by a phylogenetic comparison of partial cytochrome oxidase subunit I (COI) sequences. Chordodes formosanus is another common horsehair worm species in Taiwan, which was previously believed to specifically parasitize Hierodula mantids. However, in this study, five C. formosanus were observed emerging from an Acromantis mantid, and two long-horned grasshopper hosts (Leptoteratura sp. and Holochlora japonica). These five worms showed high degrees of similarity in COI sequences and morphology, but one of these individuals bore abnormal crowned areoles, which has never been observed in C. formosanus, and may be attributed to the incomplete development of this particular individual.

Highlights

Horsehair worms are aquatic parasites whose life cycle typically contains a free-living, aquatic phase, including mating and early larval development, and two parasitic stages, including an aquatic paratenic host stage and a terrestrial definitive host stage (Schmidt-Rhaesa 2014, Bolek et al 2015)
Acutogordius taiwanensis sp. n. is another commonly encountered species, which is usually sympatric with C. formosanus at low altitudes in Taiwan
The definitive hosts of C. formosanus are Hierodula mantids (Chiu et al 2011), whereas adults of Acutogordius taiwanensis sp. n. in Taiwan generally emerge from orthopteran insects

Summary

Introduction

Horsehair worms (phylum Nematomorpha) are aquatic parasites whose life cycle typically contains a free-living, aquatic phase, including mating and early larval development, and two parasitic stages, including an aquatic paratenic host stage and a terrestrial definitive host stage (Schmidt-Rhaesa 2014, Bolek et al 2015). Over 350 freshwater species have been described worldwide (Bolek et al 2015), but only one, Chordodes formosanus Chiu, 2011, is known in Taiwan (Chiu et al 2011). The definitive hosts of C. formosanus are Hierodula mantids (Chiu et al 2011), whereas adults of Acutogordius taiwanensis sp. Acutogordius is a small genus that consists of ten described species (de Miralles and de Villalobos 1998, Schmidt-Rhaesa and Geraci 2006, SchmidtRhaesa and Schwarz 2016) in the family Gordiidae (Poinar 2008). Holochlora japonica, were identified as C. formosanus based on morphological and molecular evidence, and added these insect species as novel definitive hosts of C. formosanus Five horsehair worm samples that had emerged from Acromantis mantids and two long-horned grasshopper species, i.e., Leptoteratura sp. and Holochlora japonica, were identified as C. formosanus based on morphological and molecular evidence, and added these insect species as novel definitive hosts of C. formosanus

Materials and methods

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Discussion