Amphialycus (Orthacarus) oblongus (Halbert, 1920),

Uusitalo, Matti, Ueckermann, Edward A. & Theron, Pieter D., 2020, A review of the family Alycidae (Acari, Acariformes) from South Africa, Zootaxa 4858 (3), pp. 301-340: 321-323

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Amphialycus (Orthacarus) oblongus (Halbert, 1920)


Amphialycus (Orthacarus) oblongus (Halbert, 1920) 

( Figs. 76–89View FIGURES 76−83View FIGURES 84−89)

Alicus oblongus Halbert, 1920: 140  , pl. 23, figs. 23a–c, erroneous orthography of Alycus C.L. Koch  ; holotype from Malahide , Ireland, from orange lichen zone at NMI ( National Museum of Ireland)  .

Pachygnathus oblongus: Thor & Willmann 1941: 138  ; Baker & Bayliss 2005: 288.

Amphialycus (Orthacarus) oblongus: Uusitalo 2010: 58  , figs. 82–87.

Alycus? roseus Womersley, 1944: 139  .

Orthacarus tremli Zachvatkin, 1949: 292  , figs. 1–5.

Description. Dorsum ( Figs. 76, 77View FIGURES 76−83). Length 300–500 μm; neotrichous setal pattern dorsally and on ventral side; naso absent, prodorsal setae vi, sce and exp sparsely ciliated (reduced), sensilla ve and sci filamentous, distances between counterparts of setae vi and anterior bothridial sensilla ve less than distance between setae in.

Venter ( Figs. 77–79View FIGURES 76−83). Genital valves each with 12–18 genital setae; anal valves terminally with 7–8 setae.

Gnathosoma  ( Figs. 76, 80–82View FIGURES 76−83). Pair of smooth cheliceral setae abaxially; rutella widening to apical lobes and a pointed process, one pair of adoral setae; distally narrow palpal tarsi with four basally fused, microtrichous eupathids.

Legs ( Fig 83View FIGURES 76−83). Claw-like empodium multisetulate; solenidial formula for tarsi, tibiae, genua and femora on legs I, II, III and IV, respectively: 2-1-0-0, 2-2-2-0, 3-2-0-1, 1-0-0-0.

Larva (n=5, Figs. 88, 89View FIGURES 84−89)

Dorsum. Length 200 μm; holotrichous; sensilla ve and sci filamentous.

Venter. Holotrichous; genital valves absent.

Gnathosoma  . One pair of fused palpal eupathids.

Legs. Solenidial formula for tarsi, tibiae, genua and femora on legs I, II and III, respectively: 1-1-0, 2-2-2, 3- 2-0, 1-0-0.

Other life stages:

Protonymph (n=6, Fig. 87View FIGURES 84−89), 1 genital seta per valve.

Deutonymph (n=8, Fig. 86View FIGURES 84−89), 4 genital setae per valve.

Tritonymph (n=6, Fig. 85View FIGURES 84−89), 11 genital setae per valve.

Adult male (n=9, Fig. 84View FIGURES 84−89), 12–18 genital setae setae, 7 pairs of eugenital setae.

Adult female (n=18, Figs. 78, 79View FIGURES 76−83), 12–18 genital setae per valve, 1 pair of eugenital setae.

Material examined. Eighteen females, 9 males, 6 tritonymphs, 8 deutonymphs, 6 protonymphs and 5 larvae from Themeda triandra  -biotope, Potchefstroom, NORTH-WEST PROVINCE, 25 March 1969, P.D. Theron. Deposited at ARC-Plant Health and Protection, Pretoria, South Africa  .

Differential diagnosis. This species easily differs from other neotrichous species of Amphialycus  by having character states typical to the subgenus Orthacarus  : without naso, prodorsal setae reduced in size, counterparts of setae vi inserted exceptionally closely to each other, basally fused palpal eupathids, short and bent legs and caudal anus ( Figs. 76, 77, 82View FIGURES 76−83). From other (still undescribed) species of the subgenus Orthacarus  , this species differs by having both pairs of prodorsal sensilla (ve and sci) filamentous, abaxially inserted cheliceral setae and a typical solenidial pattern.


Bacteria collection of National Institute of Public Health, National Medicines Institute, Poland














Amphialycus (Orthacarus) oblongus (Halbert, 1920)

Uusitalo, Matti, Ueckermann, Edward A. & Theron, Pieter D. 2020

Amphialycus (Orthacarus) oblongus:

Uusitalo, M. 2010: 58

Pachygnathus oblongus:

Thor, S. & Willmann, C. 1941: 138