Taxonomic revision of the Devonian chitinozoan <i>Ramochitina boliviensis</i> Grahn, 2002, a junior synonym of <i>Ramochitina ramosi</i> Sommer and van Boekel, 1964

A taxonomic revision of Middle Devonian chitinozoans identified as <i>Ramochitina boliviensis</i> Grahn 2002, from the Los Monos Formation in the Tacobo TCB X-1001 and Ramos R-1011 boreholes of the Tarija Basin (South Bolivia and northwestern Argentina), has been conducted. Given the morphological similarities between <i>R. boliviensis</i> and <i>Ramochitina ramosi</i>, an extensive literature review and detailed morphometric analysis were undertaken. The results indicate that both species range from the late Emsian to the middle Givetian and are restricted to Western Gondwana. Statistical analysis revealed that the overall measurements of <i>R. boliviensis</i> fall within the morphometric distribution of <i>R. ramosi</i>, with one spongy thick spine from the holotype of <i>R. boliviensis</i> considered a possible teratological form. Given the overlapping stratigraphical ranges, occurrences, and morphometrics, it is proposed that the morphological differences between <i>R. boliviensis</i> and <i>R. ramosi</i> represent intraspecific variability within <i>R. ramosi</i> or teratological forms of this species. The emendation of the species includes simple and branched spines on the same specimen. Consequently, <i>Ramochitina boliviensis</i> should be considered a junior synonym of <i>Ramochitina ramosi</i>.