Obama tribalis

Marques, Alessandro, Rossi, Ilana, Valiati, Victor Hugo & Leal-Zanchet, Ana Maria, 2018, Integrative approach reveals two new species of Obama (Platyhelminthes: Tricladida) from the South-Brazilian Atlantic Forest, Zootaxa 4455 (1), pp. 99-126: 119-120

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Obama tribalis

sp. nov.

Obama tribalis  sp. nov.

By having yellOwish dOrsal cOlOur cOvered by irregular flecks, O. tribalis  differs frOm O. argus  , O. burmeisteri  , O. evelinae  and O. riesteri  which shOw a stripped pattern ( Graff 1899; Schirch 1929; Riester 1938; Marcus 1951). Obama tribalis  , shOwing a greyish ventral cOlOur, can be distinguished frOm O. itatiayana  , which has reddish ventral cOlOur. In additiOn, O. tribalis  shOws incOnspicuOus clear halOs surrOunding the eyes, whereas in O. polyophthalma  clear halOs are cOnspicuOus, as stated abOve ( Schirch 1929; EM FrOehlich 1955; FrOehlich 1959).

Regarding the internal anatOmy, in O. tribalis  the penis papilla Occurs Only inside the male atrium, thus differing frOm O. burmeisteri  and O. riesteri  , in which the penis papilla is lOnger, Occupying almOst the entire female atrium length ( Riester 1938; Marcus 1951). In additiOn, O. riesteri  shOws a shOrt male atrium, with the gOnOduct clOser tO the insertiOns Of the penis papilla ( Riester 1938), whereas in O. tribalis  the male atrium length is similar tO that Of the female atrium. By having an OvOid and fOlded female atrium, O. tribalis  can be distinguished frOm O. argus  and O. itatiayana  , in which the female atrium is funnel-shaped and unfOlded ( Graff 1899; Schirch 1929; Riester 1938; FrOehlich 1959) and O. polyophthalma  , in which the female atrium has an ample cavity ( FrOehlich 1956). Since O. tribalis  has a straight ejaculatOry duct, it differs frOm O. evelinae  , which shOws a sinuOus ejaculatOry duct (Marcus 1951).

Obama tribalis  differs frOm O. allandra  by its external features and details Of the cOpulatOry Organs. AlthOugh bOth species exhibit part Of the dOrsal surface cOvered by irregular flecks, O. allandra  , by shOwing a yellOwish median band, which is lighter On anteriOr regiOn Of bOdy, can be distinguished frOm O. tribalis  , which shOws a hOmOgeneOusly yellOwish dOrsal cOlOur. With respect tO the cOpulatOry apparatus, bOth species present a prOstatic vesicle with fOrked prOximal pOrtiOn, but the distal pOrtiOn is pear-shaped in O. tribalis  , whereas it is wide and inverted-U shaped in O. allandra  . SOme details Of the cOpulatOry apparatus, such as the Occurrence Of glands Of the mixed type, Opening intO an invaginatiOn Of the dOrsOlateral wall Of the male atrium in O. allandra  , are absent in O. tribalis  .

In additiOn, we extend Our cOmparative analysis Of O. allandra  and O. tribalis  tO species Of Geoplana  incertae sedis, since sOme Of them have general characteristics similar tO species Of Obama  . AmOng the 47 species indicated by CarbayO et al. (2013) as Geoplana  incertae sedis, Only fOur species shOw characteristics Of the pharynx and cOpulatOry apparatus similar tO thOse Of O. allandra  and O. tribalis  . They are Geoplana beckeri ( FrOehlich, 1959)  , Geoplana caya  (du BOis-ReymOnd Marcus, 1951), G. hina (Marcus, 1951)  and G. toriba ( FrOehlich, 1958)  . By presenting a median band Only in the anteriOr regiOn Of the bOdy, O. allandra  differs frOm G. hina  and G. toriba  , which shOw a stripped pattern alOng the entire bOdy length (Marcus 1951; FrOehlich 1958). Obama allandra  shOws initially marginal eyes, which becOme dOrsal pOsteriOrly, differing frOm G. beckeri  , which has dOrsal eyes On the anteriOr tip. It alsO differs frOm G. caya  , which has Only marginal eyes ( FrOehlich 1959; du BOis-ReymOnd Marcus 1951). By having a yellOwish dOrsal cOlOur withOut stripes Or bands, O. tribalis  differs frOm all these species Of Geoplana  incertae sedis, which have striped patterns. With respect tO the cOpulatOry Organs, O. allandra  presents a distal pOrtiOn Of prOstatic vesicle inverted-U shaped and wide, differing frOm these fOur species, which have the distal pOrtiOn Of prOstatic vesicle tubular in shape (du BOis-ReymOnd Marcus 1951; Marcus 1951; du BOis- ReymOnd Marcus 1958; FrOehlich 1958). Obama tribalis  , by having the unfOrked pOrtiOn Of the prOstatic vesicle pear-shaped, can be distinguished frOm these fOur species, which have the prOstatic vesicle tubular shaped and sinuOus (du BOis-ReymOnd Marcus 1951; Marcus 1951; du BOis-ReymOnd Marcus 1958; FrOehlich 1958).

Regarding the mOlecular phylOgeny herein presented, based On the mitOchOndrial marker cytOchrOme c Oxidase subunit I gene ( COIAbout COI), likelihOOd and Bayesian analyses invariably recOvered the terminal clades with mOderate and gOOd suppOrt values. HOwever, the segment Of the COIAbout COI gene used in the analyses demOnstrated a lack Of sufficient infOrmatiOn tO sOlve mOst relatiOnships between the clOsely related cOngeneric species. This result was expected, since the COIAbout COI gene dOes nOt shOw gOOd resOlutiOn at higher taxOnOmic levels (LuO et al. 2011; Huang et al. 2013). Our results indicate the need tO use at least 600 bp Of the gene COIAbout COI in the definitiOns Of interspecific divergences and fOr species delineatiOn, at least fOr the genus Obama  . COnsidering length limitatiOn tO determine the threshOld taxOnOmic, the shOrt sequences Of O. marmorata  available On GenBank (297 pb) were insufficient tO determine the taxOnOmic divergence with O. nungara  , clOsely related species.


University of Coimbra Botany Department