Gongylonema archboldi, Kinsella, John M., Robles, Maria Del Rosario & Preisser, Whitney C., 2016

Kinsella, John M., Robles, Maria Del Rosario & Preisser, Whitney C., 2016, A review of Gongylonema spp. (Nematoda: Gongylonematidae) in North American rodents with description of a new species from the cotton rat, Sigmodon hispidus (Mammalia: Cricetidae), Zootaxa 4107 (2), pp. 277-284 : 278-282

Gongylonema archboldi n. sp.

( Figs. 1–2 )

Type host: Cricetidae : Sigmodon hispidus Say & Ord , hispid cotton rat.

Other hosts. Cricetidae : Peromyscus gossypinus (LeConte) , cotton mouse; Peromyscus polionotus (Wagner) , oldfield mouse; Podomys floridanus (Chapman) , Florida mouse; Ochrotomys nuttalli (Harlan) , golden mouse; Oryzomys palustris (Harlan) , rice rat.

Type locality. Archbold Biological Station, Highlands County Florida, U.S.A., 27° 10’ N latitude, 81° 21’ W longitude.

Other locality. San Patricio County, Texas, U.S.A., 27° 50’ N latitude, 97° 14’ W longitude.

Site of infection. Wall of anterior stomach.

Prevalence and intensity. 5 of 22 cotton rats infected with 1 to 15 worms.

Specimens deposited. Holotype USNM 1370746, allotype USNM 1405164, and paratypes USNM 1405165; Voucher specimens from Peromyscus gossypinus USNM 1370762, Podomys floridanus USNM 1370763; Sigmodon hispidus (Texas) HWML 96273, Oryzomys palustris HWML 96274.

Etymology. The species is named for Richard Archbold, pioneering biologist and founder of the Archbold Biological Station.

Description. With characteristics of the genus. Long filiform worms with prominent cuticular bosses at the anterior end, more numerous in the female than the male ( Fig. 1 A, 1B; 2A, 2B). Mouth opening rectangular with lateral constrictions opposite 2 large, lateral amphids. Three triangular teeth, 1 dorsal and 2 subventral on each side of mouth opening with a circle of 4 small papillae surrounding mouth opening. Two prominent lateral alae beginning at level of base of pharynx and extending to near the anus in both sexes ( Fig 2 C).

Male. (n=10). Body 13.0–19.0 mm (mean 17.0) long and 149–211 (182) in maximum width. Cuticular bosses at anterior end sparse, rounded, oval, or rectangular ( Fig. 1 A, 2A). Nerve ring 230–270 (250) from anterior end. Excretory pore near posterior end of muscular esophagus, 365–419 (396) from anterior end. Pharynx short, thinwalled, 32–41 (40) long. Esophagus 3082–3734 (3374) long, divided into short, anterior muscular portion 338–500 (425) long, and long, glandular posterior portion 2555–3320 (2960) long. Posterior end coiled ventrally and twisted to right, with narrow, asymmetrical caudal alae, right ala extending more anteriad than left ( Fig. 1 C). Caudal papillae asymmetrical, pedunculate and variable in number, with 5 to 6 pairs pre-cloacal and 5 to 6 pairs postcloacal. Post-cloacal pairs consist of 3 to 4 pairs of pedunculate and 1 to 2 pairs of sessile papillae near tail, often with unpaired papillae. Spicules dissimilar and very unequal in length ( Fig. 1 C, 1 D).. Right spicule boat-shaped, 97–113 (106) long, with rounded distal end and ventral depression ( Fig. 1 D, 1E). Left spicule thin, needle-tipped, 1400–1745 (1539) long ( Fig. 1 D). Gubernaculum 76–92 (81) long with a cup-shaped base in which the right spicule rests and a long irregular flange extending anteriorly on the sinistral side ( Fig. 1 E).

Podomys floridanus Ochrotomys nuttalli Peromyscus Peromyscus gossypinus polionotus

Males

Female. (n=8). Body 67.4–69.1 mm (68.3) long (n=3) by 280–381 (321) in maximum width. Cuticular bosses much more extensive than in male, rounded, oval, or rectangular, extend to about 3 mm from anterior end ( Fig. 1 B, 2B, 2D). Nerve ring 321–378 (343) from anterior end. Excretory pore at level of posterior end of muscular esophagus, 650–710 (680) from anterior end. Pharynx, short, thin-walled, 43–47 (46) long. Esophagus 6320–6573 (6465) long, divided into short, muscular anterior part, 583–680 (622) long, and long, glandular posterior part, 5640–5990 (5840) long. Circular vulva 7000–10560 (9120) from posterior end. Eggs (n=10) larvated, 57–60 (58) long by 35–38 (37) wide. Tail blunt, 235–302 (276) long.

Remarks. Of the 5 species previously reported from North American rodents, G. pulchrum is easily distinguished from G. archboldi n. sp. by its much larger size (up to 51 mm in males and 130 mm in females) and much longer left spicule (up to 20 mm). The left spicules of G. neoplasticum , G. dipodomysis , and G. peromysci are all shorter than 750 microns while that of G. archboldi n. sp. is 1400 to 1745. In addition, the female of G. dipodomysis has a very limited field of cuticular bosses and the gubernacula of G. dipodomysis and G. peromysci have very different shapes than the gubernaculum of G. archboldi n. sp. Gongylonema mysciphilia is the species most similar in measurements to G. archboldi n. sp., but this species was found in the wall of the cecum rather than the wall of the stomach, a singular anomaly within the genus. Since the description of G. mysciphilia was based only on a single male and female, it is difficult to compare measurements. However, both spicules of this species are shorter (1130 and 72) than those of G. archboldi n. sp. (1400– 1745 and 97–113), the esophagus of females is considerably shorter (3740 vs 6180–6680), as is the distance from the vulva to the tail (4800 vs 7000–10, 560).

European, Asian, and African species of Gongylonema from rodents with left spicules less than 2 mm long include G. brevispiculum Seurat, 1914 (590); G. problematicum Schulz, 1924 (430–635); G. pithyusensis Mas Coma, 1977 (623–866); G. aegypti Ashour & Lewis,1986 (318–420), and G. madeleinensis Diouf et al. 1997 (1125–1750). Only the spicules of G. madeleinensis overlap with G. archboldi n. sp. But both males (8.2 to 10.5 mm) and females (25 to 32 mm) of the former are shorter than G. archboldi n.sp and the distance from the vulva to the tail (540 to 2400) is barely a third of G. archboldi (7000–10,560). The gubernacula of all 5 species are shorter than that of the new species and also differ in shape.

Figures

FIGURE 1. Drawings of Gongylonema archboldi n. sp. A. Male, anterior end with detail of nerve ring, muscular esophagus and beginning of glandular esophagus and cuticular bosses, internal and surface view. B. Female, anterior end with detail of nerve ring, muscular esophagus and beginning of glandular esophagus and cuticular bosses, internal and surface view in two different figures. C. Male, caudal papillae asymmetrical, pedunculate and variable in number of pre-cloacal and post-cloacal papillae and sessile papillae near tail, ventral view. D. Male, spicules dissimilar and very unequal in length, right spicule boatshaped and left spicule thin, needle-tipped. E. Male, detail of gubernaculum with a cup-shaped base in which the right spicule rests.

FIGURE 2. Scanning electron micrographs of Gongylonema archboldi n. sp. A. Male, anterior end with prominent cuticular bosses, ventro-lateral view. B. Female, anterior end with more numerous prominent cuticular bosses than the male, ventral view. C. Female, detail of lateral alae, lateral view. D. Female, detail of prominent cuticular bosses.