Parapharyngodon hispidus Ferreira & Vieira & Silva & Ribeiro & Ferreira & Muniz-Pereira 2021, n. sp.
Creators: name: Ferreira, Antonio Carlos Santos
name: Vieira, Fabiano Matos
name: Silva, Diego César Nunes Da
name: Ribeiro, Leonardo Barros
name: Ferreira, Jayelen Alves
name: Muniz-Pereira, Luís Cláudio
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Nematoda
Chromadorea
Oxyurida
Pharyngodonidae
Parapharyngodon
Parapharyngodon hispidus

description: Parapharyngodon hispidus n. sp.
(Figs. 1 and 2)
General: Small, robust, whitish nematodes. Cuticle with prominent annulations beginning just behind anterior extremity and continuing to anus or cloacal aperture. Sexual dimorphism evident, males with approximately 30% of total body length of females. Males with triangular mouth aperture, with internal cuticular projections, cephalic papillae not visible, two lateral amphids, near lateroventral side of mouth (Figs. 1C, 2B). Females with star shaped mouth aperture; surrounded by three bilobed lips, one dorsal and two lateroventral, two amphids each opening on lateral lips (Figs. 1D, 2C). Oxyuriform oesophagus, ending in valved oesophageal bulb (Figs. 1A, B). Nerve ring at level of first third of oesophagus (Figs. 1A, B). Excretory pore far posterior to oesophageal bulb in both males and females (Figs. 1A, B). Males without caudal alae; caudal appendage directed dorsally (Figs. 1E, F, 2D). Lateral alae only in males (Figs. 1A, 2A).
Male (Based on 10 adult mature specimens, measurements of holotype in parentheses): Total body length 3.2–3.6 (3.2) mm, body width at level of oesophagus-intestinal junction 225–375 (270). Total oesophagus length 525–710 (525); corpus 420–530 (420) long, oesophageal bulb 110–140 (115) long, and 120–150 (125) wide. Nerve ring 138–163 (138) and excretory pore 1.2–1.5 (1.5) mm from anterior end. Lateral alae present (Figs. 1A, 2A) 1.7– 2.1 (1.7) mm long, beginning at the level of the oesophageal bulb and ending far distant to cloacal aperture. Cloacal lips smooth, not echinate (Figs. 1F, 2D–F). Posterior region with four pairs of caudal papillae (Figs. 1E, F, 2D); the first pair is subventral located immediately anterior to cloacal aperture; the second is lateral, located posterior to cloacal aperture; third pair is subventral, at level of the second pair and immediately posterior to cloacal aperture; and the fourth pair is located on caudal appendage Figs. 1E, F, 2D–F). One spicule well sclerotized 110–123 (110) long, terminating in a sharp tip (Figs. 1E, F). Gubernaculum absent. Tail conical 135–305 (175) (including caudal appendage), with a subdorsal caudal appendage 57–95 (75) long (Figs. 1E, F, 2E).
Female (Based on 10 adult mature specimens, measurements of allotype in parentheses): Total body length 7.4–10.5 (10) mm, body width at level of oesophagus-intestinal junction 720–1,160 (900). Total oesophagus length 1.3–1.7 (1.6) mm; corpus 1–1.4 (1.3) mm, oesophageal bulb 220–250 (240) long, and 250–310 (310) wide. Nerve ring 192–250 (230) and excretory pore 2.2–3.3 (2.8) mm from anterior end. Vulva not prominent (Fig. 1H), equatorial, 3.6–5.5 (5) mm from anterior end, followed by short vagina and ovijector direct posteriorly. Didelphic, uteri amphidelphic, and ovaries directed anteriorly. Both ovaries encircling isthmus and anterior region of oesophageal bulb (Fig. 1B). Eggs subovate, 67–100 long, 37–60 wide, flattened on one side, with one subapical operculum, without polar filament, early stages of cleavage in the ovijector (Figs. 1H, J, K). Eggshell thick, with punctated surface. Tail 400–590 (590) long (including spike tip) (Figs. 1G, 2G), corresponding approximately to 5.5% of total body size (mean proportional size, based on the proportional tail sizes of all females analyzed), with short spiked tip, 190–245 (210) long.
Taxonomic summary
Type host: Tropidurus hispidus (Spix) (Squamata: Tropiduridae) (Neotropical Lava Lizard, calango-de-muro)
Type locality: Campus de Ciências Agrárias (Agrarian Sciences Campus) (CCA) (09°19’41”S, 40°32’59”W) of the Universidade Federal do Vale do São Francisco (Univasf), municipality of Petrolina, state of Pernambuco, Brazil.
Site of infection: large intestine.
Prevalence: 56.85% (112 infected hosts)
Mean intensity: 4.13 ± 11.96 parasites per infected hosts
Mean abundance: 2.35 ± 10.56 parasites per analyzed hosts
Range of infections: 1–21
Type material: Holotype male (CHIOC 38994a)), allotype female (CHIOC 38994b), 2 males and 4 females paratypes (CHIOC 38994c).
Etymology: The species name of the hosts species is used as a noun in apposition to Parapharyngodon ..
Remarks: The main feature considered for the differentiation of species in Parapharyngodon and Thelandros Wedl species (Oxyurida: Pharyngodonidae) is the egg morphology and development (Bursey et al. 2013, Velarde-Aguilar et al. 2015, Rizvi et al. 2017). Therefore, the specimens evaluated in the present study were classified as Parapharyngodon since they present eggs with a subterminal operculum and in the early stages of cleavage in ovijector.
With the description of the new species the genus Parapharyngodon currently includes 55 valid species (Bursey & Goldberg 2015, Velarde-Aguilar et al. 2015, Araujo Filho et al. 2015, Garduño-Montes de Oca et al. 2016, Ramallo et al. 2016, Rizvi et al. 2017, Pereira et al. 2017, Santos et al. 2018), which can be differentiated by zoogeographic region, the presence or absence of body alae in males and females; male characteristics, such as the number and arrangement of caudal papillae, the morphology of anterior border of cloacal aperture, and the size and type of distal end of spicules; and female characteristics, such as position of the ovaries relative to the oesophageal bulb, the morphology of eggshell, and tail (Bursey et al. 2013, 2015, Velarde-Aguilar et al. 2015, Rizvi et al. 2017, Pereira, 2017).
In the Neotropical realm, ten valid species of Parapharyngodon have been described so far (Table 1). Parapharyngodon hispidus n. sp. has four pairs of caudal papillae, as do four other Neotropical species, namely, P. bainae Pereira, Sousa & Souza Lima, P. silvoi, P. sanjuanensis Ramallo, Bursey, Castillo & Acosta, and P. sceleratus. Parapharyngodon hispidus n. sp., P. silvoi, and P. sceleratus have a smooth anterior border of cloacal aperture, differing from the echinate anterior border of the cloaca of P. bainae and P. sanjuanensis (Pereira et al. 2011, 2018, Ramallo et al. 2016). Parapharyngodon hispidus n. sp. differs from P. silvoi, and P. sceleratus as the latter two have an unpaired post cloacal papilla (Freitas 1957, Vicente et al. 1993, Araujo Filho et al. 2015, Velarde-Aguilar et al. 2015), which is absent in P. hispidus n. sp.
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We highlight some considerations about two Neotropical Parapharyngodon species. Rizvi & Bursey (2013), Bursey & Goldberg (2015), and Rizvi et al. (2017) considered the females of P. alvarengai as featuring a conical tail with no spike. However, the original description of this species (see Freitas 1957) clearly shows a stout spike, which was also observed by Velarde-Aguilar et al. (2015) and Pereira et al. (2017). In the description of P. silvoi, Araujo Filho et al. (2015) describe females having ovaries extending beyond the oesophageal bulb (ovaries pre bulbar). However, we analyzed the species’ drawings in the original description and observed that the drawn female had post bulbar ovaries. Thus, we consider here the characteristics of P. silvoi demonstrated in the graphic representations.
Among the species of other zoogeographic distribution, P. hispidus n. sp. belongs to a group with four pairs of caudal papillae, without unpaired post cloacal papilla, and smooth cloacal lips (Table 2). The species composing this group are Parapharyngodon baueri Bursey & Goldberg (Afrotropical realm), P. californiensis Read & Amrein (Nearctic realm), P. jairaipurii Rizvi & Bursey (Oriental realm), P. skrjabini Vakker (Palearctic realm), and P. striatus Singh & Malhotra (Oriental realm) (Table 2). Parapharyngodon jairaipurii, described for Hemidactylus flaviviridis Ruppell (Squamata, Gekkonidae) from India, is the only species presenting the same set of characteristics of spicule tip (sharp pointed), female tail end (stout spike), and eggshell morphology (punctate) (Rizvi & Bursey 2013) (Table 2).
Although P. hispidus n. sp. and P. jairaipuri share key characteristics used to diagnose species, including sharppointed spicules, female tail ending with a stout spike, and eggs with punctated shells, other morphological and morphometric characteristics differentiate these species (Table 3). The main characteristics differentiating these species are the size of spicules (spicules of P. jairaipuri are around 55% of the size spicules of P. hispidus n. sp.) and the arrangement of the caudal papillae (two pairs of adcloacal papillae in P. jaraipuri which are absent in P. hispidus n. sp.) (Rizvi & Bursey 2013) (Table 3).
description: Published as part of Ferreira, Antonio Carlos Santos, Vieira, Fabiano Matos, Silva, Diego César Nunes Da, Ribeiro, Leonardo Barros, Ferreira, Jayelen Alves & Muniz-Pereira, Luís Cláudio, 2021, Parapharyngodon hispidus n. sp. (Nematoda: Pharyngodonidae) in Tropidurus hispidus (Spix) (Squamata: Tropiduridae) from Caatinga Biome of the Vale do São Francisco, state of Pernambuco, Brazil with a key for the Neotropical species of the genus Parapharyngodon Chatterji, pp. 185-200 in Zootaxa 4980 (1) on pages 187-193, DOI: 10.11646/zootaxa.4980.1.12, http://zenodo.org/record/4882889