Syphacia (Syphacia) brevicaudata, Weaver & Smales, 2008

Weaver, H. J. & Smales, L. R., 2008, New species of Syphacia (Syphacia) Seurat (Nematoda: Oxyuridae) from Pseudomys species (Rodentia: Muridae) from central Australia, Zootaxa 1775 (1), pp. 39-50 : 41-43

Syphacia (Syphacia) brevicaudata sp. nov.

( Figs 1–8 )

Material examined. Holotype: male from caecum, Pseudomys desertor, Mount Isa , Queensland, Australia (20 o 44’S, 139 o 27’E), 29.iv.1994, coll. M. Thomas, SAM AHC 34461.

Allotype: female, same data, SAM AHC 34462.

Paratypes: 1 male, 281 females, same data, SAM AHC 34463 .

Other material examined. From Pseudomys hermannsburgensis, Ethabuka Station , Queensland (23 o 39’S, 138 o 17’E), 4.vi.1998, 2 males, 4 females SAM AHC 34465 ; Yulara , Northern Territory (25 o 14’S, 130 o 59’E), July 1994, 1 male, 3 females, ANWC N4391 ; Nockatunga Station , Queensland (27 o 43’S, 142 o 43’E), 17.vii.1976, 11 females, SAM AHC 34464 .

Description. General: Small nematodes, cuticle with faint transverse striations. Cephalic plate oval, constricted dorsally and ventrally between mouth opening and level of amphids and cephalic papillae which are close together laterally, not on edge of plate ( Fig. 6 ). Mouth opening surrounded by 3 lips. Deirids not seen. Cervical and lateral alae absent.

Male: Length 700–1420 (n=5, =1007, sd=256.7). Maximum width 55–110 (n=5, =88, sd=21.8). Amphids 23 apart. Oesophagus length 132.5–155 (n=5, =155, sd=15.7). Oesophageal bulb 38 (n=1) long, 42.5–60 (n=5, =49, sd=6.8) wide. Nerve ring 62.5–87.5 (n=5, =76, sd=9.9), excretory pore 177.5–212.5 (n=5, =197.5, sd=15.9) anterior mamelon 207–275 (n=5, =238.5, sd=24.4) from cephalic extremity. Mamelons, 3, oval shaped, anterior mamelon 38–60 (n=5, =47, sd=10.9), middle mamelon 33.3–57.5 (n=5 =41.5, sd=9.8), posterior mamelon 35–67.5 (n=5, =51.5, sd=12.8) long. Spicule 60–67.5 (n=5, =62, sd=3.2), long, needle shaped. Gubernaculum 27.5–30 (n=5, =27.7, sd=1.9), without obvious ornamentation. Caudal alae present; 2 pairs cloacal, 2 pairs large post-anal papillae. Tail 67.5–100 (n=5, =87, sd=11.9) long, whip structure 45–70 (n=2) long.

Female: Length 1620–3375 (n=20, =2348.1, sd=575.9). Maximum width 110–168 (n=20, =141.4, sd=17.4). Amphids 31 apart. Oesophagus length 175–288 (n=20, =220.8, sd=39.7). Oesophageal bulb 44 (n=1) long, 55–105 (n=20, =68.7, sd=13.7) wide. Nerve ring 80–138 (n=20, =116.2, sd=17.1), excretory pore 187.5–430 (n=20, =309.2, sd=58), vulva 312.5–688 (n=20, =470.1, sd=105.1) from cephalic extrem- ity. Tail 260–438 (n=20, =311.1, sd=55.4) long. Eggs 113–123 (n=10, =117.5, sd=3.9) long, 33–45 (n=10,

=38, sd=4.5) wide.

Etymology. Named for the short tail length of the males, a distinguishing feature.

Remarks. This new species belongs in the genus Syphacia and subgenus Syphacia Seurat, 1916 because it has the characteristics of the genus as designated by Hugot (1988). It has neither the well developed lateral alae nor the quadrangular cephalic plate of the subgenus Cricetoxyuris Hugot, 1988 nor the short, conical tail and chitinous hook on the accessory piece of the gubernaculum that distinguish the subgenus Seuratoxyuris Hugot, 1988 . Within the subgenus, having an oval cephalic plate, with laterally situated submedian papillae, no cervical alae and the tip of the tail longer than half the total length, Syphacia (Syphacia) brevicaudata sp. nov. most closely resembles Group V, comprising S. (S.) obvelata (Rudolphi, 1802) , S. (S.) arctica Tiner & Rausch, 1950 , S.(S.) millardiae Hugot, 2005 , S. (S.) montana Yamaguti, 1943 , S. (S.) nigeriana Baylis, 1928 , and S. (S.) venteli Travassos, 1937 of Quentin (1971) and Hugot (1988; 2005) but differs from all these in having a constricted cephalic plate and two pairs of post-anal papillae.

Syphacia (S.) brevicaudata also differs from all its congeners found in the Australian bioregion in having two pairs of post-anal papillae. Four Australian species, S. (S.) abertoni , S. (S.) darwini , S. (S.) longaecauda and S. (S.) sulawesiensis , also have oval cephalic plates but only S. abertoni has a constricted cephalic plate similar in shape to that of S. (S.) brevicaudata (see Weaver & Smales 2006). Syphacia (S.) brevicaudata further differs from S. (S.) abertoni in being without cervical alae. Syphacia (S.) darwini with only two mamelons ( Hugot & Quentin 1985), S. (S.) longaecauda with a longer tail (67.5–100 compared with 370–490 in males), longer spicule (60–67.5 compared with 76–97) and longer eggs (113–123 compared with 94–100 ( Smales 2001)) and S. (S.) sulawesiensis with large lateral alae ( Hasegawa & Tarore 1996) all have an oval cephalic plate without constrictions. A quadrangular cephalic plate further distinguishes S. (S.) australasiensis and S. (S.) muris , the other species found in the region, from S. (S.) brevicaudata (see Quentin 1971; Smales 2004).

Figures

FIGURES 1–8. Syphacia (Syphacia) brevicaudata sp. nov. 1. Male, lateral view. 2. Egg, lateral view. 3. Female, lateral view. 4. Female, anterior end, lateral view. 5. Female, apical extremity, lateral view. 6. Female, en face view. 7. Male, posterior end, ventral view. 8. Male, posterior end, lateral view. Scale bars: 5, 6, 7, 8 = 25 µm; 2 = 50 µm; 1, 4 = 100 µm; 3 = 500 µm.