Pholcus, Macaronesian group, NOR detection A, C, D, F, G, I FISH B, E, H Giemsa staining A–C P. fuerteventurensis A metaphase I (a bivalent belonging to another plate is separated by a dotted line). One bivalent contains a NOR. There is also a signal on the sex chromosome trivalent. Note the scheme of sex chromosome pairing B, C two sister metaphases II separated by a dotted line. Note two terminal NORs, one on the long arm of the acrocentric pair and another one on the long arm of the acrocentric X2 chromosome D–F P. dentatus D metaphase I, one large bivalent contains a terminal NOR. Note the scheme of sex chromosome pairing E, F two fused metaphases II. Long arm of the acrocentric pair contains terminal NOR. Sister chromatids of chromosomes of this pair are sometimes associated by NOR clusters (see the right chromosome of the pair) G–I P. silvai G metaphase I, one bivalent involves a terminal NOR. Note the scheme of sex chromosome pairing H, I two metaphases II separated by dotted line. Long arm of the acrocentric pair contains terminal NOR. Abbreviations: a = chromosome of the acrocentric pair bearing NOR, b = bivalent containing NOR, s = sperm nucleus, SCT = sex chromosome trivalent, X1 = X1 chromosome, X2 = X2 chromosome, Y = Y chromosome. Scale bars: 10 μm.