Euseius nyalensis

Moraes, G. J. De, Ueckermann, E. A., Oliveira, A. R. & Yaninek, J. S., 2001, Phytoseiid mites of the genus Euseius (Acari: Phytoseiidae) from Sub­Saharan Africa, Zootaxa 3, pp. 1-70: 40-42

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Euseius nyalensis


Euseius nyalensis   (El­Badry, 1968) ( Fig. 27 View FIGURE 27 )

Amblyseius nyalensis   El­Badry, 1968: 322; Ueckermann, 1996: 28 Amblyseius neotutsi Ueckermann, 1992: 149   (new synonymy)

FEMALE (Specimens measured – Benin: 13, Cameroon: 5, Ghana: 1, Sierra Leone: 5).

Dorsum ­ Dorsal shield with few lateral striae anterior to s4 and between J2, Z1 and S2, 339(307­387) long, 229(208­249) wide. Setae j1 38(34­48), j3 47(38­58), j4 32(16­ 46), j5 38(16­56), j6 58(43­67), J2 58(43­70), J5 5(3­8), z2 39(30­48), z4 56(46­67), z5 17(10­35), Z1 55(35­64), Z4 57(48­67), Z5 80(70­91), s4 81(69­91), S2 59(46­72), S4 46(35­59), S5 46(48­59), r3 27(16­35), R1 19(14­24). All setae smooth, except Z5 which are lightly serrate.

Peritreme ­ Reaching level between j3 and z2.

Venter ­ Ventral shields smooth. Distances between ST1­ST3 63(56­70), ST2­ST2 70(62­80) and ST5­ST5 83(72­94). With 2 pairs of metapodal shields. Ventrianal shield 107(96­123) long, 53(46­64) wide at ZV2 level and 74(62­86) wide at anus level.

Spermatheca ­ Calyx trumpet­shaped in some specimens but tubular, with an abrupt increase in diameter distally in other specimens, 21(11­32) long; atrium small.

Legs – Macroseta of leg I sharp­tipped, macrosetae of other legs knobbed: Sge I 33(30­37), Sge II 31(26­32), Sge III 42(38­46), StiIII 29(24­32), Sge IV 60(50­69), StiIV 40(34­48), StIV 67(48­77).

REMARKS: The specimens collected have a considerable variation in lengths of some setae, particularly j4, j5, z5 and Z1, and of the calyx of spermatheca. They are considered to belong to a single species because of the continuous cline observed between the shortest and the longest measurements of each particular structure, the correlation between the size of the mite and the length of each of those structures and the variable lengths observed for individuals within particular populations. The average measurements of the specimens collected agree well with those of the original description as well as with those provided by Ueckermann (1996) for specimens from Yemen. All observed specimens from Sierra Leone and most specimens from Cameroon have calyx of spermatheca typically trumpet shaped, similar to the drawings of the original description and of Ueckermann (1996); those from Benin have calyx tubular, with an abrupt increase in diameter near the vesicle; 2 specimens from Cameroon have the calyx more similar to but not   typically of the later type.

SPECIMENS EXAMINED: Benin: Koko­Bante, on tree 3, 18­XI­89, G.J. Moraes; Djougou, on Gmelina   sp., 20­XI­89, G.J. Moraes; 2 km S. Cotiakou, Atacora, on Mangifera indica   , 20­XI­89, G.J. Moraes; Natitingou, on Anacardium occidentale   , 21­XI­ 89, G.J. Moraes; Glazoue, on Manihot esculenta   , 18­VII­90, A. Onzo; on A. occidentale   , 10­VI­91, A. Onzo; Ouogui, on A. occidentale   , 10­VI­91, A. Onzo; Covedji, on M. esculenta   , 17­XII­91, B. Eklou; Djougou, A. occidentale   ; 22­I­92, B. Oklou. Cameroon: Adamaoua, Tibati, on Persea americana   and M. indica   , 28­I­91, J.S. Yaninek; Adamaoua, Doualaye, on M. indica   , 29­I­91, J.S. Yaninek; 6 km S. Garoua, on Psidium guajava   , 30­I­ 91, L. Louis; Adamaoua, 2 km S. Gangui, on M. indica   , 1­II­91, L. Louis. Ghana: 0.5 km S. Dambai, Volta Region, on unidentified plant, 20­IV­90, A. Timbilla. Sierra Leone: 10 km S. Fadugu, on Gmelina arborea   , 15­XII­91, J.S. Yaninek; 31 km W. Makeni, on Ocimum viride   , 16­XII­91, J.S. Yaninek.