Tometes kranponhah and Tometes ancylorhynchus (Characiformes: Serrasalmidae), two new phytophagous serrasalmids, and the first Tometes species described from the Brazilian Shield

Abstract

Two new species of Tometes from the Brazilian Shield rapids are described. Tometes kranponhah is endemic to the Xingu River basin, whereas Tometes ancylorhynchus occurs both in the Xingu and the Tocantins-Araguaia River basins. The two species are sympatric in the Xingu drainages and have many similarities in morphology and colouration. Major diagnostic differences are the dark pigmentation on the opercle of T. kranponhah and its distinct snout shape and arrangement of premaxillary teeth. In addition, T. kranponhah is a large fish that is abundant in the Xingu River, whereas T. ancylorhynchus is a medium-sized fish for which there are few records.

A new species of Tometes Valenciennes 1850 (Characiformes: Serrasalmidae) from Tocantins-Araguaia River Basin based on integrative analysis of molecular and morphological data

“…This diagnosis was recently changed to T . ancylorhynchus by Andrade et al [11]. It is noteworthy that this lot as well as INPA 52481 ( T .…”

“…kranponhah , and M . paucisquamatus are locally referred as ‘pacu‒borracha’ (literally translated as ‘rubber pacu’), due to the rubbery texture of its flesh when cooked [11]. Notwithstanding, T .…”

“…Although U . sennaebragai is recognized only to Tapajós River Basin and occurrences outside of this basin are considered to be misidentifications [11,33], species are still reported in other watersheds such as Xingu, Tocantins-Araguaia, Madeira, Orinoco, and others [34]. This was most likely influenced by Gosline [13], which diagnosed a serrasalmid specimen (catalog CAS 20222) with a poorly-developed abdominal serra as U .…”

“…With the exception of the latter genus, Myleus clade is comprised of strictly rheophilic species and is characterized by having incisiform teeth on the jaws, two premaxillary rows of teeth that maintain inner contact, and prepelvic serra composed of thin spines not forming an abdominal keel (absent in Ossubtus xinguense ) [10,11]. The genus Tometes was taxonomically hidden for many years [12], and was hence mistaken with other serrasalmid genera, most notably Utiaritichthys , a genus that some authors consider rare and poorly-known (e.g.…”

“…Recently, most of these assignments were reported as misidentifications of Tometes because both genera show diminute prepelvic spines. However, Utiaritichthys is strictly distinguished from Tometes by having molariform teeth with two premaxillary teeth rows interspaced by a gap versus incisiform teeth with two premaxillary teeth rows lacking inner gap [11]. Tometes contains six valid species distributed in South America along drainages of Brazilian and Guiana Shields [11].…”