Labiobulura (Archaeobulura) leptomyidis Smales, 2006

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 : 5-6

Labiobulura (Archaeobulura) leptomyidis Smales, 2006

( Figs 1–3 , 95 D, 97 A, B)

Labiobulura (Archaeobulura) leptomyidis Smales, 2006 ; 63–65 ( Leptomys paulus Musser, Helgen & Lunde [as L. ernstmayeri ]).

Type host. Leptomys paulus Musser, Helgen & Lunde.

Site in host. Caecum.

Material examined. Holotype male, allotype female and paratypes from Leptomys paulus, Kawaya Village, Waruman Mountain (9° 53´S, 149° 22´E), Milne Bay Province, Papua New Guinea, coll. P. German, 7.vii.1980, SAM AHC 33916, AHC 33917, AHC 33915.

Other material examined. From Leptomys paulus Milne Bay Province: 3 males, 8 females Iana River (9° 87´S, 149° 35´E), BBM NG-109477B.

Differential diagnosis. This species can be distinguished from all congeners except L. peragale by the lack of interlabia and from L. peragale by the shape of the labial lobes which have striations on the proximal internal surfaces, and the shapes of the chordal and radial lobes of the pharyngeal portion of the oesophagus, the proportions of the cervical alae and the shape of the tail.

Distribution and hosts. Although known only from Leptomys paulus from Kawaya Village, Munimum Village and Iana River in Milne Bay Province of Papua New Guinea, this restricted distribution may be an artefact of the distribution of the small number of hosts available for dissection. The genus Leptomys is now known to have a relatively wide, if scattered, distribution across the Island of New Guinea ( Musser et al. 2008). If all known Leptomys species from their full geographic range were examined for helminths the geographical and host distributions of L. (A.) leptomyidis might well be extended. The hosts for L. (A.) leptomyidis were originally listed as Leptomys ernstmayeri and L. elegans (see Smales 2006). The genus Leptomys has since been revised and all the hosts examined for helminths have been re-identified as L. paulus (see Musser et al. 2008).

Remarks. This species differs from all congeners except L. (A.) peragale in having 6 labial lobes without interlabia. Labiobulura (A.) peragale and L. (A.) leptomyidis can be distinguished by the morphology of the cephalic end; the labial lobes of L. peragale are longer and more triangular in shape, those of L. leptomyidis shorter and rounded at the proximal end, around the inner surface of which is a ring of small fine cuticular striations ( Fig. 2 ). The chordal lobes of the pharyngeal portion of L. peragale are pyramidal, ending distally in a long central spine surrounded by 3–4 short spines while those of L. leptomyidis are more rectangular in shape and bilobed in lateral view. The spicule shaft of L. leptomyidis has a longitudinal ridge, but does not have the transverse striations along one edge found in other members of the group. The tail of both male and female L. peragale is conical and blunt, that of both male and female L. leptomyidis is extended into a pointed tip.

Smales (2006) confused the descriptions of the chordal and radial lobes of L. leptomyidi s. The chordal lobes are larger and bilobed, the radial lobes smaller and pointed. The measurements given as the length of the buccal capsule of L. leptomyidis are also in error, as they refer to the total length of the buccal apparatus, (40– 67 in males; 45–56 in females) including the pharyngeal portion of the oesophagus. The buccal capsule is 23.5 long 36.4 wide in males, 27.5 long 40 wide in females.

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 1 – 3. Labiobulura (Archeobulura) leptomyidis Smales. 1, cephalic end, en face view; 2, labial lobe, inner surface; 3, hand cut longitudinal section, buccal apparatus showing chordal and radial lobes. Scale bars: 1, 3 25 µm; 2, 10 µm.