Cytogenetic comparison of Tityus uruguayensis and a closely related undescribed species from eastern Argentina (Buthidae: Scorpiones)

ADILARDI, RENZO S.; ANDRES ALEJANDRO OJANGUREN AFFILASTRO; LILIANA MOLA

foz do Iguaçu

Congreso; 21st International Chromosome conference; 2016

21st International Chromosome conference

Tityus uruguayensis Borelli, 1901 is the only described species of the bolivianus group from lowlands ofeastern South-America; however, we have recently discovered another yetundescribed species from the same area (Tityus sp. 1). Tityus uruguayensis is widelydistributed in Uruguay and southern Brazil, while in Argentina the only knownpopulation is from an area around building ruins in El Palmar National Park(EPNP) (Entre Ríos). Tityus sp. 1 is endemic from Paraje Tres Cerros (Corrientes),an ancient isolated low altitude hilly area of subtropical eastern Argentina. Wecytogenetically compared nine males of Tityus uruguayensis from EPNP andthree males of Tityus sp. 1. Giemsa staining, C-banding and FISH with28S rDNA and (TTAGG)n telomere probes were performed. Both speciespresented holokinetic chromosomes and achiasmatic male meiosis. Tityusuruguayensis showed 2n=31 and three different cytotypes: 12II+VII atmeiosis I (seven males), 10II+VII+IV type 1 and 10II+VII+IV type 2. All themales presented the same heptavalent. Tityus sp. 1 showed two cytotypes:2n=32, 16II at meiosis I (two males) and 2n=31, 14II+III (one male). rDNAclusters were detected at one terminal region of two pairs in Tityusuruguayensis and in one pair in Tityus sp. 1. Both species showedsmall C-bands at the terminal regions of almost all chromosomes and conspicuousC-bands that colocalyzed with rDNA sites. In Tityus sp. 1, the largestchromosome of the trivalent showed one interstitial C-band, which could indicatethat it arose by one chromosome fusion. Telomeric signals were exclusivelydetected at the terminal regions of all chromosomes in both species. Thechromosome numbers found in both species are unusually high in the genus and inthe family. The presence of two NOR pairs in Tityus uruguayensis isremarkable since most of studied Buthidae species show only one NOR pair, despitethe variation in chromosome number. Funding was provided by grants from the ConsejoNacional de Investigaciones Científicas y Técnicas (CONICET PIP 00342),Universidad de Buenos Aires (UBACYT 20020130100694BA) and Agencia Nacional deProducción Científica y Tecnológica-SECyT (PICT 2010-1665).