Gint amoudensis, Kovarik, Lowe, Just, Awale, Elmi & Stahlavsky, 2018

Just, Pavel, Šťáhlavský, František, Kovařík, František & Štundlová, Jana, 2022, Tracking the trends of karyotype differentiation in the phylogenetic context of Gint, a scorpion genus endemic to the Horn of Africa (Scorpiones: Buthidae), Zoological Journal of the Linnean Society 196 (2), pp. 885-901 : 892-893

GINT AMOUDENSIS

T h e m o s t s t r i k i n g i n t r a s p e c i f i c v a r i a b i l i t y i s discovered in G. amoudensis , which exhibits four cytotypes differing in the diploid number, multivalent associations and in the number and position of 18S rDNA sites. The cytotypes II, III and IV occur sympatrically, while the cytotype I (S1325) is found in a remote locality Borama c. 150 km far from the other cytotypes.

Cytotype I (1Ƌ; S1325) exhibits 2 n = 36 chromosomes, which decrease in length from 4.49% to 1.63% of DSL (Supporting Information, Fig. S2C ; Table S2). The post-pachytene nuclei show 16 bivalents and one quadrivalent (chromosomes 1, 2, 9 and 15) ( Fig. 3A ; Supporting Information, Fig. S2C ). Three 18S rDNA sites are detected ( Fig. 3B ), two of them are located in the subterminal region of the chromosomes 1 and 2 involved in the quadrivalent and one in the terminal position of chromosome 2 in the quadrivalent (Supporting Information, Fig. S2C ).

Cytotype II (1 Ƌ; S1291) has 2 n = 35 chromosomes, which decrease in length from 5.01% to 1.45% of DSL (Supporting Information, Fig. S2D ; Table S2). The post-pachytene spermatocytes exhibit 14 bivalents, one trivalent (chromosomes 4, 24 and 35) and one quadrivalent (chromosomes 1, 5, 8 and 23) ( Fig. 3C ; Supporting Information, Fig. S2D ). Three 18S rDNA loci are present ( Fig. 3D ), one pair is located on the chromosomes 1 (subterminal site) and 5 (terminal site) involved in the quadrivalent, and one single heterozygous locus is situated in the interstitial region of the third largest bivalent (chromosome 9; Fig. 3D ; Supporting Information, Fig. S2D ).

Cytotype III (1 Ƌ; S1293) has 2 n = 36 chromosomes, which decrease in length from 4.71% to 1.52% of DSL (Supporting Information, Fig. S2E ; Table S2). The post-pachytene cells show 15 bivalents and one hexavalent (chromosomes 1, 2, 5, 6, 11 and 24) ( Fig. 3E ; Supporting Information, Fig. S2E ). One pair of 18S rDNA sites is located in the subterminal region of the chromosomes 1 and 2 of the hexavalent ( Fig. 3F ; Supporting Information, Fig. S2E ).

Cytotype IV (1 Ƌ; S1292) exhibits 2 n = 35 chromosomes, which decrease in length from 4.66% to 1.54% of DSL (Supporting Information, Fig. S2F ; Table S2). The post-pachytene nuclei show a configuration of 13 bivalents, one trivalent (chromosomes 7, 26 and 35) and one hexavalent (chromosomes 1, 4, 5, 6, 10 and 23) ( Fig. 3G ; Supporting Information, Fig. S2F ). One pair of 18S rDNA sites is located in the subterminal region of the chromosomes 1 and 4 involved in the hexavalent ( Fig. 3H ; Supporting Information, Fig. S2F ).

Figures

Figure 2. Post-pachytene cells of Gint species after Giemsa staining (A, C, E, G, I, K, M, O) and FISH with 18S rDNA (red signals) (B, D, F, H, J,L, N, P).A, B,G. banfasae cytotype I(2n=18 –7II + IV).C, D, G. banfasae cytotype II (2n= 18 – 6II +VI). E, F, G. banfasae cytotype III (2n = 19 – 5II + III + VI). G, H, G. dabakalo cytotype I (2n = 23 – 9II + V). I, J,G. dabakalo cytotype II (2n = 24 – 8II + III + V). K, L, G. dabakalo cytotype III (2n = 27 – 8II + 2III + V). M, N, G. gaitako (2n = 30 – 13II + IV). O, P, G. maidensis (2n = 34). Abbreviations: II, bivalent; III, trivalent; IV, quadrivalent; V, pentavalent; VI, hexavalent. Arrowheads indicate the position of 18S rDNA. Scale bar = 10 µm.

Figure 3. Post-pachytene cells of Gint amoudensis and G. gubanensis after Giemsa staining (A, C, E, G, I) and FISH with 18S rDNA (red signals) (B, D, F, H, J). A, B, G. amoudensis cytotype I (2n = 36 – 16II + IV). C, D, G. amoudensis cytotype II (2n = 35 – 14II + III + IV). E, F, G. amoudensis cytotype III (2n = 36 – 15II + VI). G, H, G. amoudensis cytotype IV (2n = 35 – 13II + III + VI). I, J, G.gubanensis (2n = 45 – 21II + III). Abbreviations: II, bivalent; III, trivalent; IV, quadrivalent; VI, hexavalent. Arrowheads indicate the position of 18S rDNA. Scale bar = 10 µm.