Macroponema comani Mawson, 1978

Sukee, Tanapan, Jabbar, Abdul & Beveridge, Ian, 2020, Revision of MaCroponema Mawson, 1978 (Nematoda: Strongylida) from macropodid marsupials with the description of two new species, Parasites & Vectors (298) 13 (1), pp. 1-21 : 12-14

Macroponema comani Mawson, 1978

Type-host: Macropus giganteus Shaw (Marsupialia: Macropodidae ).

Type-locality: Yan Yean (37°34 ′ S, 145°06 ′ E), Victoria, Australia .

Type-material: Holotype ♂ ( SAM AHC 41156 ); allotype ♀ ( SAM AHC 41157 ).

Additional material examined: Queensland: 2 ♀♀, 53 km N of The Lynd Junction ( SAM AHC 48882 ) ; 1 ♀, 29 km N of The Lynd Junction ( SAM AHC 48877 ) ; 3 ♂♂, 13 ♀♀, Hervey’s Range , Townsville ( SAM AHC 6393 ) ; 3 ♂♂, 15 ♀♀, Oak Valley , Townsville ( SAM AHC 24250 , 32767 ) ; 13 ♀♀, Townsville ( SAM AHC 7640 ) ; 3 ♂♂, 2 ♀♀, Woodstock ( SAM AHC 7641 ) ; 3 ♂♂, 5 ♀♀, Landsdown Station via Woodstock ( SAM AHC 7672 ) ; 10 ♀♀, 5 km S of Reid River ( SAM AHC 32759 ) ; 2 ♂♂, 2 ♀♀, Mingela ( SAM AHC 7396 , 7826 ) ; 1♂, 3 ♀♀, Jumba Station via Charters Towers ( SAM AHC 48879 ) ; 13 ♂♂, 30 ♀♀, Pallamana Station via Charters Towers ( SAM AHC 13354 , 13416 ) ; 31 ♂♂, 65 ♀♀, Harvest Home Station via Charters Towers ( SAM AHC 13384 , 13385 , 13383 , 13427 ) ; 1 ♂, Inkerman Station via Home Hill ( SAM AHC 7658 ) ; 1 ♂, 1 ♀, Homestead ( SAM AHC 32564 ) ; 11 ♂♂, 25 ♀♀, 6 km W of Prairie ( SAM AHC 31715 ) ; 1 ♂, 1 ♀, 20 km N of Clermont ( SAM AHC 48875 ) ; 1 ♂, 1 ♀, 14 km N of Clermont (50 E) ; 1 ♂, 20 km S of Barcaldine ( SAM AHC 31624 ) ; 1 ♂, 1 ♀, Bogantungen ( SAM AHC 24265 ) ; 8 ♂♂, 2 ♀♀, 66 km N of Rockhampton ( SAM AHC 12132 ) ; 2 ♂♂, 1 ♀, 40 km N of Rockhampton ( SAM AHC 11091 ) ; 2 ♂♂, 3 ♀♀, Rockhampton ( SAM AHC 11061 ) ; 2 ♂♂, 2 ♀♀, Mount Hay via Rockhampton ( SAM AHC 32479 ) ; 1 ♂, Darling Plains Station via Banana ( SAM AHC 19905 ) ; 3 ♂♂, 3 ♀♀, 15 km S of Wowan ( SAM AHC 48876 ) ; 1 ♂, 2 ♀♀, 6 km W of Warwick ( SAM AHC 48880 ) ; 2 ♂♂, 2 ♀♀, 5 km E of Oman Ama ( SAM AHC 48878 ) ; 2 ♂♂, 1 ♀, Killarney ( SAM AHC 19908 ) ; New South Wales : 1 ♂, 3 ♀♀, Ebor ( SAM AHC 11073 ) ; 4 ♂♂, 12 ♀♀, Kingstown ( SAM AHC 11074 ) ; Australian Capital Territory: 1 ♀, Tidbinbillla ( SAM AHC 10942 ) ; Victoria: 6 ♂♂, 68 ♀♀, Yan Yean ( SAM AHC 9593 , 9595 , 9597 , 9600 , 9625 , 9622 , 9626 , 9627 , 9661,11208 ) ; 7 ♂♂, 8 ♀♀, Dartmouth ( SAM AHC 9218 ) ; 1 ♀, Bellbird ( SAM AHC 9727 ) ; 1 ♀, Mitta Mitta ( SAM AHC 12054 ) ; 9 ♂♂, 21♀♀, Marlo ( SAM AHC 23001 ) .

Representative DNA sequences: Molecular voucher from M. giganteus (50 km N of The Lynd Junction; SAM 48882 ) : GenBank : MT080023 ( ITS 1 , 5.8 S and ITS 2 ) .

Description

General. Robust, whitish nematodes. Cephalic collar absent; mouth dorso-ventrally elongate; elevation on each side of mouth opening bears lateral amphid and 2 dome-shaped sub-median papillae; papillae with 2 short, anteriorly-directed setae. Buccal capsule elongate, dorso-ventrally elongate, poorly sclerotised, with partially sclerotised annulus in anterior half; shelf projects into buccal capsule at anterior extremity of buccal capsule, not visible in all specimens; buccal capsule supported externally by strong radial musculature in posterior half; sclerotised annulus at junction of buccal capsule with oesophagus; oesophagus elongate; corpus widening posterior to nerve-ring; posterior half of corpus with c. 20 sets of bead-like sclerotised projections in lining, one arising from each sector of oesophagus; isthmus narrow, elongate; bulb elongate; intestinal cells enlarged at anterior extremity, surrounding posterior part of oesophageal bulb. Nerve-ring in anterior oesophageal region; excretory pore at level of oesophageal bulb; deirids at level of buccal capsule.

Male [Measurements of 10 specimens; Figs. 29–41.] Total length 12.0–17.0 (14.1); maximum width 0.45–0.68 (0.58); buccal capsule 0.10–0.12 (0.11) long, 0.06–0.09 (0.08) wide; oesophagus 2.40–3.05 (2.65); nerve-ring from anterior extremity 0.58–0.72 (0.68); excretory pore from anterior extremity 2.28–3.68 (2.76); deirid from anterior extremity 0.12–0.15 (0.13). Bursal lobes poorly separated; lateral lobes slightly longer than ventral and dorsal lobes; no median indentation in dorsal lobe; ventro-ventral and ventro-lateral rays apposed, reach margin of bursa; externo-lateral ray divergent from lateral trunk, not reaching margin of bursa; medio-lateral and postero-lateral rays apposed in distal half, fused in proximal half, reaching margin of bursa; externo-dorsal ray arising from lateral trunk, stout, not reaching margin of bursa; dorsal ray slender at origin, divides at mid-length; branches arcuate, internal branchlets reaching margin of bursa; external branchlets very short, arise soon after principal bifurcation, terminate in elevations on internal surface of bursa. Spicules elongate, alate; alae with numerous, fine, transverse striations; anterior extremity irregularly knobbed; distal extremity blunt-tipped; alae terminate abruptly anterior to spicule tip, lose striations prior to termination; spicule length 1.70–1.98 (1.81); gubernaculum absent; central cordate and paired lateral thickenings of spicule sheaths present. Ventral lip of genital cone large, conical, bearing papilla 0; dorsal lip with paired bifid appendages.

Female [Measurements of 10 specimens. Figs. 42–44.] Total length 18.0–27.0 (21.1); maximum width 0.67–0.94 (0.85); buccal capsule 0.12–0.16 (0.14) long, 0.08–0.11 (0.09) wide; oesophagus 2.95–4.32 (3.36); nerve-ring from anterior extremity 0.70–0.87 (0.80); excretory pore from anterior extremity 2.88–4.05 (3.50); deirid from anterior extremity 0.13–0.21 (015). Tail short, conical, straight, 0.41–0.60 (0.48) long; vulva 0.85–1.45 (1.29) from tip of tail; vagina short, 0.55–0.95 (0.78) long, slightly sinuous; distal uterus narrow, enlarging and becoming filled with eggs proximally; proximal tip of uterus bulbiform (seminal receptacle), with narrow duct leading to ovary; egg ellipsoidal 0.10–0.12 (0.11) long, 0.06–0.07 (0.06) wide.

Remarks

The present redescription confirms that of Mawson [ 1] but provides additional details including egg sizes and a line drawing of the genital cone, which was illustrated by a scanning electron micrograph only by Mawson [ 1]. The transverse section of the oesophagus illustrated by Mawson [ 1] (figure 16 in [ 1]) suggests that the bead-like thickenings lining the oesophagus are arranged in pairs on each segment (dorsal and two subventral) of the oesophagus. This is not the case (Fig. 36) and a single structure is present for each segment of the oesophagus at each level. Mawson [ 1] commented on the plasticity of the buccal capsule providing ventral and sublateral views with the buccal capsule in collapsed and expanded positions. Similar variation was observed in the specimens here, but the illustrations presented in the redescription are limited to a ventral view with the buccal capsule collapsed. Mawson [ 1] did not illustrate or describe the complex array of muscles running between the wall of the buccal capsule and the longitudinal musculature shown here. They are similar in their arrangement to those described by Beveridge [ 21]. The illustrations of Beveridge [ 21] complement those presented here and have not been included in the present redescription along with the projections into the lumen of the buccal capsule at its anterior extremity. Beveridge [ 21] considered the host of his specimens of M. comani to be O. robustus which he noted was unusual. However, examining the range of nematodes collected from this individual host and the fact that it was collected at the same time as the material from Ma. giganteus , it seems most likely that the original host identification was in error and consequently the material (SAM AHC 13354) has been included above under Ma. giganteus .

Although a wide range of specimens was available, very few were gravid, probably accounting for the lack of any description of the egg by Mawson [ 1]. However, in some of the new specimens, the entire female reproductive tract was visible (Fig. 44) and indicated that unlike in species of other genera of the Cloacininae, the distal uterus is narrow and tubular, eventually becoming saccate anteriorly, with eggs largely restricted to the saccate region. In addition, a seminal receptacle is detectable at the proximal extremity of the uterus (Fig. 44). The central cordate and paired lateral thickenings of the spicule sheaths characteristic of the family [ 22], have not been reported previously for this genus, but are here illustrated in Figs. 38 and 39.

The current data confirm the restriction of this species to a single host, Ma. giganteus , but indicates that its distribution extends from Victoria to northern Queensland ( Fig. 45 ).

Figures

Fig. 45 Distribution of Macroponema comani Mawson,1978 from Macropus giganteus in eastern Australia. Closed circles represent localities at which the parasite has been collected; open circles indicate locations at which kangaroos have been examined but the nematode has not been found.The stippled area indicates the known geographical range of M.giganteus