Spauligodon xenosauri, Bursey, Charles R., Goldberg, Stephen R. & Telford, Sam R., 2007

Bursey, Charles R., Goldberg, Stephen R. & Telford, Sam R., 2007, New species of Spauligodon (Nematoda: Pharyngodonidae) in Xenosaurus platyceps (Squamata: Xenosauridae) from Mexico, Zootaxa 1501, pp. 65-68 : 65-67

Spauligodon xenosauri n. sp.

( Figs 1–8 )

General: Small nematodes, cylindrical body tapering anteriorly, truncate posteriorly; moderate sexual dimorphism, males about one third length of recently gravid females to one-fifth length of fully gravid females. Cuticle with fine, regular transverse striations, 1–2 apart and distinct annuli, 6–8 wide in males, 15–18 wide in females. Lateral alae present in males, absent in females. Mouth opening triangular, bounded by 3 bilobed lips, 6 cephalic papillae; 2 lateral amphids present. Esophageal bulb separated from corpus by small constriction.

Male: Based on 10 specimens. Small, white, fusiform nematodes; distinctly truncated posterior end. Length excluding tail filament 1.35 ± 0.10 mm (1.18–1.47 mm), width at level of excretory pore 191 ± 12 (179–217). Lateral alae extending from level of nerve ring to anterior border of caudal alae; widest (approximately 60) at posterior end. Mouth opening bounded by 3 bilobed lips. Esophageal corpus 240 ± 15 (214–256) in length; esophageal bulb length 68 ± 4 (61– 73); esophageal bulb width 74 ± 5 (61–79). Nerve ring 115 ± 7 (98–122) and excretory pore 445 ± 61 (357–510) from anterior end, respectively. Posterior end terminating dorsally in elongated filiform tail and laterally in narrow caudal alae. Three pairs of caudal papillae present; precloacal pair situated on slightly inflated portion of caudal end and ventrally directed, first postcloacal pair ventrolaterally directed; both enclosed by caudal alae. Second postcloacal pair situated at base of filiform tail spike, not enclosed by caudal alae. Flexible filiform tail spike extends 326 ± 19 (306–357) beyond second pair postcloacal papillae; 2–4 cuticular spines on proximal third of length. Spicule poorly sclerotized, sharply pointed distal end, 37 ± 2 (34–40) in length. Cloacal lips smooth, unadorned.

Female: Based on 14 gravid specimens. Small, brownish, cylindrical nematodes, tapering anteriorly, truncate posteriorly. Length excluding tail filament 4.65 ± 1.40 mm (2.62 – 7.17 mm); individuals with very few eggs on average 3.0 mm in length, individuals distended with eggs on average 6.7 mm. Width at level of esophageal-intestinal junction 415 ± 65 (288–512). Esophageal corpus 649 ± 41 (587–714) in length, esophageal bulb 117 ± 10 (104–134) long, 133 ± 6 (122–140) wide. Nerve ring 146 ± 15 (128–166); excretory pore 909 ± 148 (689–1,122), and vulva 1,059 ± 180 (803– 1,352) from anterior end, respectively. Thick walled muscular ovijector extends posteriorly continuing as thin-walled vagina joining 2 uteri, both directed posteriorly and parallel to one another reaching posterior end before turning anteriorly. Ovarian and uterine coils post bulbar but extend into the portion of body cavity posterior to anus. Uterus and ovary seen only in nongravid females and females with few eggs. In larger females filled with eggs the internal structure are not visible. Anus 610 ± 178 (383–893) from attachment point of tail filament. Flexible tail filament 1,104 ± 67 (896–1,088), 1–3 short cuticular spines on proximal half. Eggs ovoid, operculate 97 ± 3 (92–101) in length, 41 ± 2 (39–43) in width; pronucleus stage of development.

Taxonomic summary

Type host: Xenosaurus platyceps King and Thompson, 1968 , flathead knob-scaled lizard, symbiotype, UF 104135.

Type locality: Tamaulipas State, Mexico, 22.3 km SW Rio San Marcos.

Site of infection: Large intestine.

Prevalence: 4 of 10; 40%.

Mean intensity and range: 13.5 ± 9.1, 7–27.

Type specimens. Holotype: male, USNPC 98046. Allotype, female, USNPC 98047. Paratypes, USNPC 98048. Voucher specimens, USNPC 98049.

Etymology. The new species is named for its host.

Remarks. Species of Spauligodon are identified on the basis of the presence or absence of a spicule, the presence or absence of spines on the tail filament of adults, egg morphology, and geographical distribution ( Bursey et al., 2005). Chabaud and Brygoo (1962) have suggested that geographical distribution is the most important factor in the speciation of reptilian oxyurids.

Three species, Spauligodon garciaprietoi Jiménez-Ruiz, León-Règagnon and Campbell, 2003 , Spauligodon giganticus ( Read and Amrein, 1953) and Spauligodon oxkutzcabiensis (Chitwood, 1938) , have been reported in Mexican reptiles (Chitwood, 1938; Read and Amrein, 1953; Jiménez-Ruiz et al., 2003); three additional species, Spauligodon californiensis ( Read and Amrein, 1953) , Spauligodon golbergi Bursey and McAllister, 1996 and Spauligodon mearnsi (Edgerly, 1952) , are known from reptiles of the southwestern United States. Spauligodon xenosauri n. sp. is easily separated from these species by egg morphology: eggs fusiform in S. giganticus and S. oxkutzcabiensis ; ellipsoid in S. californiensis , ovoid in S. xenosauri n. sp., barrel-shaped in S. garciaprietoi , S. goldbergi and S. mearnsi ; both ends with adornment in S. oxkutzcabiensis , one end with adornment in S. giganticus , pole adornment absent in S. xenosauri n. sp., one end truncate in S.californiensis , both ends truncate and plugged in S. garciaprietoi , S. goldbergi and S. mearnsi . Spauligodon xenosauri n. sp. should be added to Table I of Bursey et al. (2005): male characters, spicule 37 µm, tail with 2–4 spines; female characters, filiform tail with 1–3 spines, ovoid egg. In the key provided by Jiménez-Ruiz (2003), S. xenosauri n. sp. would be identified at 4a but would need differentiation from S. mearnsi : 4.1a, eggs barrel shaped ….. S. mearnsi ; 4.1b, eggs ovoid ….. S. xenosauri n. sp.

Figures

FIGURES 1 – 8. Spauligodon n. sp. (1) Female, non-gravid, anterior end, lateral view. (2) Female, en face view. (3) Spicule. (4) Eggs, pronucleus stage. (5) Male, posterior end, semidiagrammatic lateral view, spines exaggerated. (6). Female, non-gravid, posterior end, lateral view, spines exaggerated. (7). Male, entire, ventral view. (8). Male, posterior end, semidiagrammatic ventral view.