Morphological, molecular characterisation and phylogenetic position of Longidorus mindanaoensis n. sp. (Nematoda: Longidoridae) from a Philippine Avicennia mangrove habitat

Abstract

Longidorus mindanaoensis n. sp. is described from samples associated with riverine mangroves in the Philippines and is the first Longidorus species collected from such a habitat. Its relationship within the genus is inferred from molecular and morphological data. Phylogenetic inferences were performed for D2-D3 and SSU rDNA using appropriate phylogenetic algorithms. The new species is characterised by a thickened basal layer of the body cuticle with prominent spiral fibres, a dome-shaped continuous lip region, an oval to elliptical fovea with pore-like opening, the guiding ring at 2.2-2.5 lip region diam. from the anterior end, very weakly developed odontophore, all three pharyngeal gland nuclei at about the mid-point of the basal bulb, vulva at 30-39%, tail convexconoid to hemispherical, shorter than anal body diam., males with 19-24 ventromedian supplements, and four juvenile stages, all with the replacement odontostyle at a short distance from the functional one. On the basis of amphid shape and structure, shape of anterior body region and general body shape, L. mindanaoensis n. sp. comes close to L. caespiticola, L. eridanicus, L. helveticus, L. macrosoma, L. poessneckensis, L. orongorongensis, L. waikouaitii and L. belondiroides. D2-D3 analysis placed the new species as sister to L. pisi and the two combined are sister clade to a monophyletic group that includes (L. poessneckensis (L. caespiticola (L. helveticus, L. macrosoma))). However, on the basis of SSU phylogeny, L. mindanaoensis n. sp. is positioned within a clade that includes (Longidorus sp. (L. mindanaoensis n. sp. (L. poessneckensis (L. helveticus, L. macrosoma)))). The 'close' relationship of the new species with L. pisi in the D2-D3 tree is incongruent with the widely different morphology of the two species. The other species that are close to the new species in the cladogram are in agreement with the morphology.

First report of Longidorus mindanaoensis Coomans, De Ley, Jimenez and De Ley, 2012 (Nematoda: Longidoridae) From a Mangrove Forest in Vietnam

“…However, new morphometric data ranges were recorded for the species as follows: the females and males of the presently studied population of L. mindanaoensis from Vietnam are smaller than the type population (Table 1), and therefore, related indices, including a, b are also relatively smaller compared with the data given for the type population. The present observation is in accordance with the results of Coomans et al (2012) and Archidona-Yuste et al (2016) showing the body length of Longidorus spp. could be highly variable (Coomans et al, 2012;Archidona-Yuste et al, 2016).…”

“…The morphological comparisons revealed the studied population belongs to Longidorus mindanaoensis (Coomans et al, 2012) that was recovered from the same habitat in the Philippines by Coomans et al (2012). The morphological characters and measurements of the Vietnamese population of L. mindanaoensis (Fig.…”

Characterization of Longidorus caespiticola (Nematoda: Longidoridae) from the Czech Republic

“…Morphometrics of the Czech populations (female) compared with the type (Hooper, 1961), Belgian (Sturhan, 1963) and Slovenian (Širca & Urek, 2009) In recent years it has become a standard to identify species on the basis of morphological and molecular data with more emphasis on molecular work (Coomans et al, 2012). Therefore in this work five markers of ribosomal and mitochondrial DNA have been analyzed and compared.…”

Morphological and molecular characterisation of Paralongidorus plesioepimikis n. sp. (Nematoda: Longidoridae) from southern Spain

“…Outgroup taxa for each dataset were selected on the basis of their relationships in previously published large sub-unit (LSU) and small sub-unit (SSU) phylogenies (Holterman et al, 2006;Palomares-Rius et al, 2008;Coomans et al, 2012). The newly obtained and published sequences for each gene were aligned using ClustalW (Thompson et al, 1997) with default parameters.…”