Ficophagus chaozhouensis n. sp. (Nematoda: Aphelenchoididae), an associate of Ficus hirta Vahl var. roxburghii (Miq.) King in China

Abstract

SummaryA new nematode species was recovered from the syconia of Ficus hirta var. roxburghii from Chaozhou, Guangdong, China. It is described herein as Ficophagus chaozhouensis n. sp. and is characterised by possessing the combined characters of a short post-uterine sac, excretory pore located near the head, amoeboid sperm, three pairs of subventral papillae on the male tail, rounded male tail tip with mucron (occasionally swollen), absence of gubernaculum (or apophysis), a blunt rosethorn-shaped spicule without a terminal cucullus, and a digitate rostrum with a broadly squared tip. Ficophagus chaozhouensis n. sp. was separated from other sequenced species by differences in the partial small subunit (SSU) rRNA gene and D2-D3 expansion segments of the large subunit (LSU) rRNA gene. Phylogenetic analysis with LSU D2-D3 expansion segment sequences suggested that F. chaozhouensis n. sp. is clustered in the same highly supported monophyletic clade with F. aculeata, F. maxima and F. yoponensis, and is sister to F. aculeata.

Phylogenetic position of Ptychaphelenchus eucalypticola Hodda, 2009 within the Aphelenchoidoidea Skarbilovich, 1947 (Siddiqi, 1980) inferred from partial 18S and 28S rDNA gene sequences

“…This seems plausible as P. eucalypticola shares a number of morphological similarities with species of Ficophagus, including a general similarity in body shape, finely annulated cuticle, a robust stylet, a pharyngeal bulb with a post-median valve, a vulva with protruding or overhanging lips, a vagina perpendicular or anteriorly directed, and an anterior genital branch extending to overlap the pharyngeal glands (Hodda, 2009;Davies et al, 2015). Most species of Ficophagus have excretory pores opening in the cephalic region (Davies et al, 2015(Davies et al, , 2017a(Davies et al, , b, 2020Zeng et al, 2019Zeng et al, , 2020Zhang et al, 2019) although a few have an excretory pore opening in the vicinity of the nerve ring and pharyngeal intestinal junction (see Zhao et al, 2022) which is the condition in P. eucalypticola (Hodda, 2009). There are, however, a number of morphological differences between P. eucalypticola and species of Ficophagus.…”

“…There are, however, a number of morphological differences between P. eucalypticola and species of Ficophagus. Ptychaphelenchus eucalypticola possesses a labial disc, which species of Ficoph- agus lack (Davies et al, 2015(Davies et al, , 2017aZeng et al, 2019Zeng et al, , 2020Zhang et al, 2019;Zhao et al, 2022), with the exception of Ficophagus richardi Davies & Bartholomaeus, 2020, which has a 'labial cap' (Davies et al, 2020). The spicules in males of P. eucalypticola have a more depressed capitulum and a slighter condylus than in species of Ficophagus.…”

“…The spicules in males of P. eucalypticola have a more depressed capitulum and a slighter condylus than in species of Ficophagus. Species of Ficophagus have males with 2-3 pairs of caudal papillae, always with one pair about mid-tail length; the other one or two pairs may be found either pre-cloacal, or near the tail tip (Davies et al, 2015(Davies et al, , 2017a(Davies et al, , b, 2020Zeng et al, 2019Zeng et al, , 2020Zhang et al, 2019;Zhao et al, 2022). Conversely, in P. eucalypticola there are three pairs of caudal papillae, two just posterior to the cloaca, and the third pair slightly more posterior, but not at mid-tail length (Hodda, 2009).…”

“…Davies et al (2015) included in the diagnosis for the genus Ficophagus that species have tails that may or may not be mucronate, and although many species have been described with mucronate tails (Davies et al, 2017a;Zeng et al, 2019Zeng et al, , 2020Zhao et al, 2022); these mucrons are small and typically fairly simple, quite unlike that of P. eucalypticola, which has a distinct tripartite protuberance, consisting of a ventral and two subdorsal digits. There is also a significant ecological difference between P. eucalypticola and species of Ficophagus: P. eucalypticola is associated with the outer bark of Eucalyptus macrorhyncha, whereas species of Ficophagus have an intimate association with Ficus fig sycones and fig-pollinating wasps (Davies et al, 2015(Davies et al, , 2017a(Davies et al, , b, 2020Zeng et al, 2019Zeng et al, , 2020Zhao et al, 2022). As above, in comparison with Aphelenchoides, the overall evidence indicates that P. eucalypticola represents a distinct aphelenchoid lineage.…”