Luzarinae, Hebard, 1928

Timm, Vítor Falchi, Martins, Luciano De Pinho, Acosta, Riuler Corrêa, Szinwelski, Neucir, Pereira, Marcelo Ribeiro, Costa, Maria Kátia Matiotti Da & Zefa, Edison, 2021, Trends of karyotype evolution in the Neotropical long-legged crickets Phalangopsidae (Orthoptera, Grylloidea), Zootaxa 4938 (1), pp. 101-116 : 103-104

Luzarinae

In the four analyzed species of Luzarinae , we found the karyotype with 2n = 11♁ in I. puri , 2n = 12♁ in L. susurra , 2n = 13♁ in M. ornata , and 2n = 18♀ in L. lata ( Figs 1–4 ). All of them presented X0♁-XX ♀ sex-determining system, except L. susurra with the Neo-XY♁-XX ♀; the X (and Neo-X) chromosomes are metacentrics with the same size of the largest bivalents of the karyotype; the Neo-Y chromosome of L. susurra is a small acrocentric ( Fig. 5 , Tabs 1–2).

Izecksohniella puri and M. ornata showed symmetrical karyotypes with all M/SM chromosomes, and FN = 20 and 24, respectively. In M. ornata both bivalents of the pair 1 presented chromosomes with secondary constriction and sattellite ( Fig. 3 , arrow). Luzaridella susurra has an irregular karyotype, with FN = 16, composed of two pairs of large submetacentrics (1 and 2), but the pair 1 with CI closer to the limit for an acrocentric chromosome; both twice the size of the pairs 3 (small metacentric), 4 and 5 (small acrocentrics). Luzarida lata presented asymmetric karyotype, with FN = 28, composed of six pairs of M/SM chromosomes, and two pairs of acrocentrics (pairs 7 and 8). In the last two species, acrocentric bivalents are among the smallest chromosomes of the complement ( Figs 1–4 , Tabs 1–2).

Meiosis. We did not obtain meiotic divisions in I. puri and L. lata , since all analyzed specimens were adult females; we found metaphases I in L. susurra , with a pair of heteromorphic homologues that represent the Neo-XY chromosomes, both connected by a terminal chiasma ( Fig. 5 ); in M. ornata we found diplotenes with all metacentric bivalentes (ring-shaped) joined by a terminal chiasma, and the X chromosome differing from bivalentes by its rodshaped ( Fig. 6 ).

Figures

FIGURES 1–4. Habitus and karyotype of Luzarinae species. 1, Luzaridella susurra, 2n=12, XX♀; 2, Luzarida lata, 2n=18, XX♀; 3, Melanotes ornata, 2n=13, X0♁, pair 1 present secondary constriction and satellite (arrow); 4, Izecksohniella puri, 2n=12, XX♀. Photography 1, 2 by Luciano de Pinho Martins, 3 by Marcelo Pereira Ribeiro, 4 Edison Zefa.

FIGURES 5–6. Cells meiosis showing the sex-determining system in two species of Luzarinae. 5, diakinesis/metaphase I of Luzaridella susurra ♁ with Neo-XY sex-detemining system; 6, diplotene of Melanotes ornata♁ with all bivalents containing terminal chiasma, and X univalent.