Gongylonema alecturae Johnston &Mawson, 1942

Spratt, David M., 2023, Redescription of species of Gongylonema Molin, 1857 (Nematoda: Spiruroidea Gongylonematidae) parasitic in some Australian vertebrate hosts and description of three new species, Zootaxa 5239 (2), pp. 204-220 : 205-207

Gongylonema alecturae Johnston &Mawson, 1942

Gongylonema alecturae Johnston & Mawson, 1942, pp. 92–93 , figs 1–2.

Type specimens. Holotype ♂, allotype ♀ AHC 41286; “co-type” male mounted on slide AHC 21270.

Type locality. Eidsvold , Qld., Australia .

Type host. Alectura lathami J.E. Gray , ( Aves, Galliformes , Megapodiidae ) (Australian brush-turkey).

Site of infection. Unstated.

Material examined. From Alectura lathami: Eidsvold Qld : types; 2 ♂♂, 3 ♀♀, fragments from bile duct of liver, (AHC 705).

Description ( Fig. 1 A–F .)

General: Nematodes with marked sexual dimorphism, cuticular bosses (= verruciform cuticular thickenings) present on anterior end, with prominent transverse cuticular striae. Cephalic end with peri-buccal ring, buccal capsule present. Oral opening dorso-ventrally elongated, 2 pairs of internal papillae, 2 pairs of cephalic papillae and 2 large lateral amphids. (Lack of material precluded en face preparation.) Deirids situated anteriorly, near origin of lateral alae. Oesophagus long, divided into anterior muscular and posterior glandular regions.

Male (holotype in italics, “ co-type” male + 2 males (AHC 705) in parentheses): Total length 31.3, 28.7 (37, 31) mm. Maximum width 222, 212 (270, 297). Cuticular bosses initially on all surfaces, confined to lateral surfaces from about junction of muscular and glandular oesophagus, extending 541, 421 (795, 403) from cephalic extremity. Buccal capsule 42, 42 (33, 33) long, 17, 19 (21, 15) wide. Deirids immediately anterior to lateral alae, 114, 119 (146, 125) from anterior end. Lateral alae present, continue along entire body length, widening to form asymmetric caudal alae, right wider than left, extending to tail tip. Nerve ring 193, 187 (250, 283) from anterior end, excretory pore not observed in types, 468, 348 from anterior end in other specimens. Muscular oesophagus 385, 343 (493, 503) long, glandular oesophagus 4617, 4189 (5009. 5300)long.Spicules unequal, markedly different in length, right spicule 124, 104 (104, 125) long, 21, 23 (20, 21) maximum width; left spicule 17280, 15476 [broken, missing] long, finely striated; portion of gubernaculum accommodating left spicule 83, 94 (94, 83) long, portion accommodating right spicule 37, 42 (40, 39) long. Tail twisted, with 6 pairs of pedunculated pre-cloacal and 3 pairs of pedunculated post-cloacal papillae; 1 or 2 pairs of smaller sessile post-cloacal papillae, variably distributed.Tail 156 (damaged) (198, 218) long.

Female (allotype in italics + 3 females (AHC 705) in parentheses): Total length 76 mm 64 (61–67). Maximum width 318, 329 (318–345) at tail end. Dense cuticular bosses on all surfaces initially, confined to lateral surfaces from about junction of muscular and glandular oesophagus, extending 1007, 733 (636–822) from cephalic extremity. Buccal capsule 42, 42 (40–43) long, 17, 21 (19–23) wide. Deirids anterior to origin of lateral alae, 104, 117 (73– 160) from anterior end. Nerve ring 125, 284 (249–354), excretory pore 555, 450 (424–489) from anterior end. Muscular oesophagus 608, 588 (504–647), glandular oesophagus 7364, 6953 (5883–7950) long. Vulva 16762, 14487 (12700–17274) from posterior extremity. Tail –, 235 (209–260). Larvated eggs 56, 54 (52–59) long, 37, 36 (31–39) wide, with thick, smooth shells.

Remarks. Gongylonema alecturae was described by Johnston and Mawson (1942) from the brush-turkey, Alectura lathami , collected by T. L. Bancroft at Eidsvold Qld. The date of collection and the tissue site in the host were not mentioned. The only other material available from the brush-turkey (AHC 705) was represented by two males, three females and a number of female fragments collected from the liver and bile ducts of A. lathami (as Catheturina lathami ) in August 1918 by T.H. Johnston at Eidsvold, Qld.

The location of specimens in the bile duct of the liver of A. lathami (AHC 705) is unusual because all the specimens collected from macropodids and attributed to G. alecturae came from the oesophageal and gastric mucosae. AHC 705 contains a portion of liver, including bile duct from which I recovered a worm fragment. Unfortunately, there is no left spicule in one of the males and it is broken off at the distal end in the other, precluding absolute certainty with respect to the specific identification. However, other morphological features of males and females fall well within those of G. alecturae and it is placed therein.

The tiny papillae detected on the specimen with a twisted tail would be exceptionally difficult to detect in most males as the tails are normally twisted. The tail tip was markedly contracted in the allotype and it was not possible to discern the posterior intestine, rectum and anus and consequently the tail length. It was recorded as 0.16 mm by Johnston and Mawson (1942).

Specimens from brush-turkeys are here recognised as G. alecturae on the basis of the morphology of the spicules, especially the characteristically barbed tip of the left spicule, the complex gubernaculum which accommodates both left and right spicules, the number and distribution of pre- and post-cloacal pedunculated papillae, the former invariably six pairs, the latter with three pairs of large pedunculated and one or two pairs of smaller non-pedunculated papillae arranged variably.

Specimens from the brush-turkeys differ from those from agile wallabies and grey kangaroos in the difference in site of infection, the much more simple morphology of the right spicule including shorter length and narrower width, the greater length of left spicule, the shorter distance bosses extend beyond the cephalic extremity in females, the shorter length of muscular and glandular oesophagus and of tail in both sexes, and the much greater distance of the vulva from the tail tip in females, much more pronounced in females from N. agilis than from M. giganteus .

Many more macropodids than brush-turkeys have been examined in north Queensland and the specimen from Queensland Museum, GL 11304, collected from the oesophagus of N. agilis in 1913 by Fielding suggests that what was thought to be G. alecturae , but here recognised as G. macropodum sp. nov., has been known from macropodids but unrecognised for almost a century ( Speare et al., 1983).

The greater body length of males and females, the greater length and characteristic barbed tip of the left spicule, with the anterior spike longer and more acute and the greater distance of the vulva from the tail tip distinguishes G. alecturae from all other species described in this text. In addition, the long glandular oesophagus in females is another distinguishing feature from all but G. bettongiae sp. nov.

Figures

FIGURE 1 A–F. Gongylonema alecturae Mawson, 1942. A, Cephalic end female, lateral view. B, Vulva and vagina, allotype female, ventral view. C, Posterior end male holotype, ventral view. D, Left spicule distal extremity, co-type male, lateral view. E, Right and left spicules and gubernaculum, co-type male, lateral view. F, Posterior extremity female, lateral view. Scale bars: Fig. 1A, 1B–1E = 50 µm, Fig. 1F = 100 µm.