Labiobulura (Labiobulura) peramelis ( Baylis, 1930 ) Mawson, 1960

Smales, Lesley R., 2009, A review of the nematode genus Labiobulura (Ascaridida: Subuluridae) parasitic in bandicoots (Peramelidae) and bilbies (Thylocomyidae) from Australia and rodents (Murinae: Hydromyini) from Papua New Guinea with the description of two new species, Zootaxa 2209, pp. 1-27 : 16-21

Labiobulura (Labiobulura) peramelis ( Baylis, 1930) Mawson, 1960

( Figs 64–78 , 95 C, 96D, E, 98E, F, 99)

Labiobulura peramelis Mawson, 1960: 278 –279 (bandicoot); Inglis 1958: 595 –596, 1960; 129; Quentin, 1969: 475. Subulura peramelis Baylis, 1930: 356 –359 figs 3–5 (stomach?, I. macrourus [as Perameles obesulus ]; nec Johnston & Mawson 1939a: 204; Johnston & Mawson 1951: 36 ( I. macrourus [as I. torosus ]).

Aulonocephalus peramelis Chitwood & Chitwood, 1938: 67 .

Type host. I. macrourus (Gould) .

Site in host. Caecum, colon.

Material examined. Cotypes 2 males, 3 females from Isoodon macrourus Rollingstone North Queensland, coll. W. Nicoll, 29. ix. 1915, BMNH 1938.7.18.1-3, QM GL11514.

Other material examined. From Isoodon auratus 24 males, 50 females, no coll data, SAM AHC 33140. From Isoodon macrourus Queensland; 7 males, 20 females north Queensland SAM AHC 4529, 12 males, 15 females no coll. data QM GL12639, SAM AHC 769, 7 males, 15 females Townsville SAM AHC 7906, 8 males, 12 females Atherton CSIRO N1534, 37 males, 36 females Rockhampton SAM AHC 11067, 33193, 33254, 33283, 33250, 3325533184, 33186, 9 females Yeppoon SAM AHC 33213, 250 males, 250 females Gladstone SAM AHC 33285, 33285, 33286, 12 males Shoalwater Bay CSIRO N3625, 1 female Darra SAM AHC 30318, 17 males, 30 females Yandina SAM AHC GL14493, 70 males, 74 females Brisbane CSIRO N146, SAM AHC 33064: Northern Territory; 134 males, 153 females Darwin CSIRO N4962, 4965, SAM AHC 27304, 33199, 33212, 4706, 33204, 33208, 5 males, 5 females Bees Creek SAM AHC 33208: Western Australia; 122 males, 159 females Kimberley WAM V1712, 1725, 1727, 141 males, 131 females Mitchell Plateau CSIRO N1962, SAM AHC 13019, 13020, 13027, 33135.

Differential diagnosis. Labiobulura (L.) peramelis differs from all congeners except L. (L.) baylisi and L. (L.) inglisi in having interlabia. It differs from both of these in the morphology of the labial lobes, the placement of the submedian papillae, the shape of the denticles, the proportions of the buccal apparatus, the shapes of the chordal and radial lobes of the pharyngeal portion of the oesophagus.

Description. General: Robust, medium sized worms. Cuticle with annulations; cervical alae wide. Mouth opening bounded by 6 labial lobes, 4 submedians triangular in outline, each with double papilla below base, 2 laterals longer, rectangular, blunt proximal ends, each with amphid on base; 4 rectangular interlabial with narrowed bases, 2 triangular interlabia without papillae, oriented 3 dorsally, 3 ventrally; proximal end of each lateral lobe and the rectangular interlabial lobes with irregularly trilobed denticle. Buccal capsule circular in cross section, separated from pharyngeal portion by fine transverse ridge, pharyngeal portion of the buccal apparatus may be as wide or wider than long. Pharyngeal lobes cuticularized; 3 larger rectangular chordal lobes, 3 smaller bifid radial lobes, project anteriorly into buccal cavity; not extending to base of buccal capsule. Chordal and radial lobes neither helical nor spiral; peripheral lobes form cup for chordal and radial lobes. Oesophagus widens gradually to terminal bulb, about1/7 to 1/9.4 body length. Nerve ring surrounds anterior oesophagus; excretory pore posterior to nerve ring.

Male: Measurements of worms from Western Australian localities followed by measurements from Baylis 1930. Length 10–14 (12.3), 7.7–9.2 mm; width 255–408 (345), 300–333. Buccal apparatus maximum dimensions 37.4–82.5 (55.6), 50–62.5 long 34–92.4 (51.24), 45–55 wide; buccal capsule 13.2–23.1 (17.6) long 19.8–33 (25.7) wide. Oesophagus 1700–2066 (1792), 1500 long; bulb 228–254 (239), 210–250 long 154–241 (211), 210–270 wide. Nerve ring 465–536 (488), 350–450, excretory pore 683–804 (744), 528–820, from anterior end. Spicules similar, slender with longitudinal ridge, transverse striations along one edge, proximal ends simple, distal tips pointed 1930–2610 (2225), 2000–2200 long, about 1/5.5 body length. Gubernaculum with sides extending anteriorly, 165–198 (180), 150–170 long. Tail 178–234 (217.7), 200 long. Sucker pre cloacal, elongate, without cuticular elaborations 550–1100 (826) from tail tip; 11 pairs caudal papillae, 3 pairs pre cloacal, 2 pairs at level of cloaca, 6 pairs post cloacal.

Female: Measurements of worms from Western Australian localities followed by measurements from Baylis (1930). Length 19–21 (19.7), 11–12.75 mm; width 391–459 (428), 350–400. Buccal apparatus maximum dimensions, 42.5–75.9 (56.4) long, 47.6–59.4 (55.6) wide; buccal capsule 15.3–25.5 (18.7) long 23.1–32.3 (27.7) wide Oesophagus 1853–2346 (2094), 1800 long; bulb 295–435 (311) long 234–308 (276.6) wide. Nerve ring 478.5–543 (523.7); excretory pore 737–824 (813) from anterior end. Vulva simple, unornamented, in anterior half of body, 7255–7905 (7618), 4500–5600 from anterior end, about 1/2.6 body length. Tail elongate, tapering to conical tip 816–986 (911), 400–560 long. Eggs embryonated, thin shelled, sub globular 59.4–62.7 (61.5) by 52.8–59.4 (55.3), 67.5–87.5.

Larvae: Length 3100–4300 (3690), width 124–140.7 (126.9). Oesophagus 675–1050 (872) long; nerve ring 221–265 (241), excretory pore 284, 274 (2 measurements) from anterior end. Tail 80–182 (115) long. Distribution and hosts. Although the type host was identified by Baylis (1930) as Perameles obesula this is probably in error for Isoodon macrourus as explained above for L. baylisi . No specimens of L. peramelis have been found in collections of P. nasuta , which has a similar distribution in Queensland, and is therefore unlikely to be the type host. Any records of L. peramelis from I. obesulus from Queensland are similarly in error and should be attributed to I. macrourus (see Mackerras & Mackerras 1960). Labiobulura peramelis mirrors the distribution of its bandicoot host across northern Australia and as far south as Brisbane on the east coast, but has not been collected in northern New South Wales, despite the fact that I. macrourus is found in suburban gardens as far south as Sydney ( Gordon 2008). Finding L. peramelis in I. auratus (Ramsay) is a new host record and finding L. peramelis in the Kimberley and Mitchell Plateau regions of Western Australia and localities around Darwin in the Northern Territor y are new locality records.

Remarks. Labiobulura (L.) peramelis differs from all congeners except L. (L.) baylisi and L. (L.) inglisi in having 6 labial lobes with interlabia, and from L. (L.) baylisi and L. (L.) inglisi in the shape of the rectangular interlabia, only those of L. peramelis have narrowed bases, and the shape of the lateral labial lobes, rectangular in L. peramelis , broader with a rounded bases in L. baylisi , and having papillae below rather than on the lobes in L. inglisi . Labiobulura peramelis further differs from L. baylisi in not having a nuchal constriction of the anterior end, having a more variable sized buccal apparatus, 37.4–82.5 in males compared with 46–59.5 and a bilobed, not conical radial lobe. Labiobulura peramelis further differs from L. inglisi in having tri lobed not quadri lobed denticles, a wider buccal apparatus, 34–92.5 long compared with 19–42.5 long in males, rectangular not elongated chordal lobes extending into the buccal cavity and in the shape of the radial lobes, shorter, bilobed in L. peramelis conical in L. inglisi .

The larvae observed in one collection from I. macrourus were twice as long as those of L. inglisi with more developed anterior structures. Since there was no apparent sexual differentiation, however, they were also thought to be third stage larvae.

Figures

FIGURE 95. Scanning electron micrographs of anterior ends of Labiobulura (Labiobulura) spp. A, L. baylisi; B, L. inglisi; C, L. peramelis; D, L. quentini. Scale bars: 20 μm.

FIGURES 64 — 78. Labiobulura (Labiobulura) peramelis Baylis. 64, anterior end male, lateral view; 65, cephalic end, en face view, 66, cephalic end optical section dorso-ventral view; 67, cephalic end, optical section lateral view; 68, mid buccal apparatus, hand cut transverse section; 69, spicule tip, lateral aspect; 70, buccal apparatus, hand cut longitudinal section showing chordal and radial lobes; 71 spicule shaft; 72, alae, hand cut transverse section; 73, spicule, proximal end; 74, male tail, ventral view; 75, vulva, lateral view; 76, gubernaculum, lateral view; 77, female tail, lateral view; 78, male tail, lateral view. Scale bars: 64, 74, 77, 78, 200 µm; 65, 68 – 73, 75, 76, 25 µm 66, 67, 50 µm.