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Showing posts with label River basin: Orinoco. Show all posts
Showing posts with label River basin: Orinoco. Show all posts

Sunday, April 7, 2024

[Ichthyology • 2024] Monotocheirodon duda • A New characid Species with remarkable sexual dimorphism (Characiformes: Characidae: Stevardiinae) from the upper Guayabero River, Orinoco Basin, Colombia


Monotocheirodon duda
Carvalho, Thomaz, Urbano-Bonilla & Prada-Pedreros, 2024
 
 
Abstract
A new species of characid with remarkable sexual characteristics is described from the upper Guayabero River drainage from the Orinoco basin in Colombia. The new species is included in the genus Monotocheirodon by sharing most of the previously proposed diagnostic features of this genus. It differs from all Stevardiinae by the combination, in adult males, of an enlarged urogenital papilla in contact with the first anal-fin unbranched ray and a highly modified anal fin with enlarged and distally elongated first and second branched anal-fin rays, forming a gonopodium-like structure. In addition, it differs from congeners by the presence of an adipose fin, an incomplete lateral line, an ascending process of the premaxilla dorsally oriented, and a long snout. The new species was discovered from a poorly sampled region in Colombia and is an unexpected new record given its disjunct geographic distribution from other species of the genus. Monotocheirodon species were previously known from piedmont drainages in Bolivia and Peru. The conservation status of the new species is herein categorized following IUCN criteria.

Keywords: endemism, insemination, Monotocheirodon, sexual characters, South America, species diversity

Lateral view of live specimens of Monotocheirodon duda showing live colouration. Above a male and below a female specimen. Specimens not cataloged.

 Monotocheirodon duda, new species

Diagnosis: The new species differs from all Stevardiinae species by the combined presence in adult males of an enlarged urogenital papilla (length about one-third to half of the first unbranched ray), which is in contact with the first anal-fin unbranched ray and a highly modified anal fin, with enlarged (anteroposteriorly) and distally elongated first and second branched anal-fin rays, forming a gonopodium-like structure (Figure 2). The new species differs from all other species of Monotocheirodon by the presence of an adipose fin (Figure 1, vs. absent); lateral line incomplete, pored scales not reaching the caudal fin (vs. lateral line complete); ascending process of the premaxilla dorsally directed (Figure 3, vs. strongly bent posteroventrally); and a longer snout that occupies about a fourth of the head length (HL), between 23.1% and 30.0% of HL (vs. short snout, <20% of the HL).

Etymology: Monotocheiron duda is named after the river where the new species was captured, mostly tributaries to the Duda River or captured in the Duda River itself (type locality). In Spanish, the epithet specific “duda” means doubt, which also refers to its presumed placement into the genus Monotocheirodon, an assumption that needs further evaluation.


Tiago P. Carvalho, Andréa Tonolli Thomaz, Alexander Urbano-Bonilla and Saúl Prada-Pedreros. 2024. A New characid Species with remarkable sexual dimorphism (Characiformes: Characidae: Stevardiinae) from the upper Guayabero River, Orinoco basin, Colombia. Journal of Fish Biology. DOI: 10.1111/jfb.15738

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Sunday, February 25, 2024

[Herpetology • 2024] Eunectes akayima • Disentangling the Anacondas: Revealing a New Green Species and Rethinking Yellows


Eunectes murinus (Linnaeus, 1758) 
Eunectes akayima Rivas, De La Quintana, Mancuso, Pacheco, Rivas, Mariotto, Salazar-Valenzuela, Tepeña Baihua, Baihua, Burghardt, Vonk, Hernandez, García-Pérez, Fry & Corey-Rivas, 2024

E. notaeus Cope, 1862 

 
Abstract
Anacondas, genus Eunectes, are a group of aquatic snakes with a wide distribution in South America. The taxonomic status of several species has been uncertain and/or controversial. Using genetic data from four recognized anaconda species across nine countries, this study investigates the phylogenetic relationships within the genus Eunectes. A key finding was the identification of two distinct clades within Eunectes murinus, revealing two species as cryptic yet genetically deeply divergent. This has led to the recognition of the Northern Green Anaconda as a separate species (Eunectes akayima sp. nov.), distinct from its southern counterpart (E. murinus), the Southern Green Anaconda. Additionally, our data challenge the current understanding of Yellow Anaconda species by proposing the unification of Eunectes deschauenseei and Eunectes beniensis into a single species with Eunectes notaeus. This reclassification is based on comprehensive genetic and phylogeographic analyses, suggesting closer relationships than previously recognized and the realization that our understanding of their geographic ranges is insufficient to justify its use as a separation criterion. We also present a phylogeographic hypothesis that traces the Miocene diversification of anacondas in western South America. Beyond its academic significance, this study has vital implications for the conservation of these iconic reptile species, highlighting our lack of knowledge about the diversity of the South American fauna and the need for revised strategies to conserve the newly identified and reclassified species. 

Keywords: cryptic diversity; Boidae; South America; Llanos; Pebas system; Orinoco basin; redundant species



Eunectes akayima sp. nov.

Etymology: 
We propose the common name, Northern Green Anaconda, for Eunectes akayima sp. nov. Before the arrival of the Spaniards, northern Venezuela was occupied by various Indigenous nations, among which the Caribs were an important group. Several Carib nations remain including the Kariña, Panare, Yekuana, Pemones, and Akawaio. The word for anaconda in various Cariban languages is a variant of akayima/okoyimo/okoimo, in which akayi/okoyi/okoi means “snake” and the suffix -ima/-imo means “large”. The suffix -ima/-imo does not necessarily mean ‘large’ in a physical sense. Rather, it is used to denote the kind of largeness that indicates a different category of being. The literal translation of akayima is “The Great Snake” (S. Gildea pers. comm.). The species name akayima is pronounced as follows: əkəyimə in standard dictionary pronunciation font; ŭkŭyēmŭ using the phonics; and uh-kuh-yee-muh using the Plotkin method for English-like writing to capture Cariban language pronunciations [Plotkin, 1994]. The word akayima is also used to refer to the rainbow, probably associated with a feathered serpent in their belief system that came out after rains to dry its feathers [Gumilla, 1740]. We, therefore, acknowledge the culture of these Indigenous people who share their territories with this species by adopting their word for anaconda as the specific epithet for this new species. We propose the common name for E. murinus as Southern Green Anaconda, to promote taxonomic stability for the most widely distributed species and avoid confusion. Table 6 provides a comparison between the E. akayima sp. nov. holotype, one of its paratypes, and the E. murinus lectotype.
Previous work had identified other candidate species and subspecies of the anaconda in the Orinoco basin with somewhat similar distribution to E. akayima [Dunn & Conant, 1936]. However, all of these differences have been found to be inconsistent [Dirksen, 2002; Dirksen & Henderson, 2002; Dirksen & Bohme, 1998]; therefore, these synonyms are all invalid. In addition, the word “akayima” has been indigenously used to designate this species for at least hundreds (and perhaps even thousands) of years before the use of any of the other synonyms. It was certainly in use in 1758 when the Code started counting names as valid; so, akayima is clearly the senior synonym. This is, admittedly, an unorthodox position regarding the International Code of Zoological Nomenclature [1999], which prefers the names that have been published in Western science as “valid”. However, it is well due time that Western science starts recognizing the ancestral knowledge and cultural legacy of non-Westernized society. If we respect and honor the culture of these original nations, accepting akayima as the senior synonym is unavoidable.


Conclusions: 
This study provides the most extensive sampling of anacondas to date and raises new questions about the distinctive lineages, geological history, and conservation status of the Eunectes group. Historical, geographic, and landscape-scale events may have shaped the current distribution and composition of the species. Looking at the ecology of present-day anacondas, it would seem that the entire Amazon/Orinoco basin would be an area of free dispersal for anacondas. However, the presence of a new cryptic species in the north and the E. murinus in the south tells us that we still know very little about the gene flow dynamics of a large vertebrate in the world’s most diverse terrestrial ecosystem. The idea that there could be a population of E. notaeus living throughout the Amazon basin that has managed to evade detection thanks to a coloration that superficially resembles that of E. murinus is puzzling, and speaks loudly to the need for thorough sampling to better document the diversity we still have.


 Jesús A. Rivas, Paola De La Quintana, Marco Mancuso, Luis F. Pacheco, Gilson A. Rivas, Sandra Mariotto, David Salazar-Valenzuela, Marcelo Tepeña Baihua, Penti Baihua, Gordon M. Burghardt, Freek J. Vonk, Emil Hernandez, Juán Elías García-Pérez, Bryan G. Fry and Sarah Corey-Rivas. 2024. Disentangling the Anacondas: Revealing a New Green Species and Rethinking Yellows. Diversity. 16(2), 127. DOI: 10.3390/d16020127
(This article belongs to the Special Issue DNA Barcoding for Biodiversity Conservation and Restoration)


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Wednesday, July 20, 2022

[Ichthyology • 2022] Astronotus mikoljii • A New Species of Astronotus (Teleostei: Cichlidae) from the Orinoco River and Gulf of Paria Basins, northern South America


Astronotus mikoljii 
Lozano, Lasso-Alcalá, Bittencourt, Taphorn, Perez & Farias, 2022

Mikolji’s Oscar | Oscar de Mikolji  ||  DOI: 10.3897/zookeys.1113.81240

Abstract
Based on morphological and molecular analysis of Astronotus species, a new species is described from the Orinoco River and Gulf of Paria basins in Venezuela and Colombia. Morphologically, it differs from Astronotus crassipinnis and Astronotus ocellatus in pre-orbital depth, caudal peduncle depth, head width, and caudal peduncle length, with significant differences in average percentage values. Osteologically, it differs from the two described species by lacking a hypurapophysis on the parahypural bone (hypural complex) and having two or three supraneural bones. Another characteristic that helps diagnose the new species is the morphology of the sagitta otolith, which is oval with crenulated dorsal and ventral margins and a rounded posterior edge. Genetically, the new species is distinct from all the other lineages previously proposed for the genus, delimited by five single locus species delimitation methods, and also has unique diagnostic nucleotides. Phylogenetic analyses support the monophyly of the new species as well as all other species/lineages. Astronotus species have considerable genetic, anatomical, and sagitta otolith shape differences, but have few significant traditional morphometric and meristic differences, because there is high variability in counts of spines, soft dorsal-fin rays, and lateral-line scales. It is clear that this new species is genetically and anatomically differentiated from all other species within the genus, and deserves recognition as a new valid species.

Keywords: DNA, fish, freshwater, morphometrics, osteology, sagitta otoliths, taxonomy

Astronotus mikoljii sp. nov., preserved holotype MCNG 56677 (240.12 mm SL),
Venezuela., Estado Apure, Municipio Pedro Camejo in a small stream tributary of Arauca River.
Photograph: Ivan Mikolji.


Astronotus mikoljii sp. nov., 
A live coloration of specimens collected with holotype
B Natural shallow pond and type locality in floodplain of Arauca River Venezuela.
Photographs: Ivan Mikolji.

 Astronotus mikoljii sp. nov.

Diagnosis: The new species is distinguished from congeners by the following combination of characters: two or three supraneural bones (Fig. 4) (vs. two); absence of the spinous process (hypurapophysis) on the anterosuperior border of the parahypural bone (hypural complex) in Astronotus mikoljii sp. nov. (vs. present in A. ocellatus and A. crassipinnis) (Fig. 5). The sagitta otolith in A. mikoljii sp. nov. is oval, with strongly crenulated ventral and dorsal margins (vs. elliptical and smooth-lobed margins in A. crassipinnis, and elliptical and smooth-dentate margins A. ocellatus); the rostrum is projected with an elongated process, in A. mikoljii sp. nov. (vs. rostrum process short in A. crassipinnis and A. ocellatus); the posterior region of the sagitta otolith is rounded in A. mikoljii sp. nov. (vs. straight or flat in A. crassipinnis and A. ocellatus) (Fig. 6). The aspect ratio of sagitta otoliths in A. mikoljii sp. nov. (AR = 0.665) is higher than that of A. ocellatus (AR = 0.606), and A. crassipinnis (AR = 0.585), and the differences are statistically significant at P < 0.05. The roundness index was highest in A. mikoljii sp. nov. (Rd = 0.597) vs. A. ocellatus (Rd = 0.545) and A. crassipinnis (Rd = 0.543) (P < 0.05). Also the morphometric index showed higher values in A. mikoljii sp. nov. compared to A. ocellatus (0.837 vs. 0.767) and A. crassipinnis (0.735) (Suppl. material 1: Table S2). The new species also is distinguished from congeners by the following combination of morphometric characters: the mean head length of A. mikoljii sp. nov. (36.72% SL) is longer than that of A. crassipinnis (35.01% SL), and also A. ocellatus (33.26% SL); the mean diameter of the orbit of A. mikoljii sp. nov. (9.06% SL) is greater than that of A. ocellatus (7.36%SL) and that of A. crassipinnis (7.73% SL); the mean pre-orbital depth of A. mikoljii sp. nov. (14.22% SL) is greater than that of A. crassipinnis (10.14% SL) but less than that of A. ocellatus (15.91% SL); the mean snout length of A. mikoljii sp. nov. (11.53% SL) is longer than that of A. crassipinnis (5.36% SL), and A. ocellatus (10.67% SL) (Tables 1, 2).


Etymology: The specific name is given to honor Mr. Ivan Mikolji, Venezuelan explorer, artist, author, underwater photographer, and audiovisual producer, in recognition for being a tireless and enthusiastic diffuser of the biodiversity and natural history of freshwater fishes, conservation of aquatic ecosystems of Venezuela and Colombia, and for logistic support for this work. Since 2020, Ivan Mikolji has been recognized as Associate Researcher of the Museo de Historia Natural La Salle, from the Fundación La Salle de Ciencias Naturales, in Caracas, Venezuela.

Common names: In Spanish and indigenous local languages, names which are known for Astronotus mikoljii sp. nov. in Venezuela are pavona, vieja, cupaneca, Oscar, mijsho (Kariña), boisikuajaba (Warao), hácho (Pumé = Yaruro), phadeewa, jadaewa (Ye’Kuana = Makiritare), perewa, parawa (Eñepá = Panare), yawirra (Kúrrim = Kurripako), kohukohurimï, kohokohorimï, owënawë kohoromï” (Yanomami = Yanomamï) (Barandiarán 1962; Mago 1967, 1970c; Novoa et al. 1982; Obregón et al. 1984; Román 1985; Novoa 1986; Román 1988; Bedoya 1992; Mattei-Müller et al. 1994; Lasso and Machado-Allison 2000; Mosonyi 2002; Machado-Allison 2003; Vispo and Knab-Vispo 2003; Mattei-Müller and Serowe 2007; Brito et al. 2011) and pavo real, carabazú, Oscar, mojarra, mojarra negra, eba (Puinave), Itapukunda (Kurripako), uan (Tucano) in Colombia (Sánchez 2008). 
The suggested common name for this species in the aquarium hobby is “Mikolji’s Oscar” in English, “Oscar de Mikolji ‘’ in Spanish.



Alfredo Perez Lozano, Oscar M. Lasso-Alcalá, Pedro S. Bittencourt, Donald C. Taphorn, Nayibe Perez and Izeni Pires Farias. 2022. A New Species of Astronotus (Teleostei, Cichlidae) from the Orinoco River and Gulf of Paria Basins, northern South America. ZooKeys. 1113: 111-152. DOI: 10.3897/zookeys.1113.81240


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Thursday, April 1, 2021

[Herpetology • 2021] Kataphraktosaurus ungerhamiltoni • Discovery of An Additional Piece of the Large Gymnophthalmid Puzzle: A New Genus and Species of Stream Spiny Lizard (Gymnophthalmidae: Cercosaurinae) from the western Guiana Shield in Venezuela


Kataphraktosaurus ungerhamiltoni 
Rojas-Runjaic, Barrio Amorós, Señaris, De la Riva & Castroviejo-Fisher, 2021
 
DOI: 10.11646/zootaxa.4950.2.4 
 twitter.com/RojasRunjaic
Researchgate.net/publication/350471802

Abstract
Gymnophthalmids are a highly diverse group of Neotropical lizards and its species richness is still in process of discovery. The incorporation of molecular evidence and a noticeable increase in taxon and geographic sampling in systematic studies has led to the description of numerous new genera and species of gymnophthalmids (particularly in Cercosaurinae) in recent years. Herein we describe a new genus and species of cercosaurine lizard with crocodile-like morphology, from the Venezuelan Guiana Shield on the basis of molecular phylogenetic and morphological evidence. Kataphraktosaurus gen. nov. can be readily distinguished from all other genera of Cercosaurinae by a unique combination of morphological characters that includes heterogeneous dorsal scalation with enlarged and strongly keeled scales forming two paravertebral rows, ventral and subcaudal scales imbricated and strongly keeled, large and symmetrical cephalic scales, absence of postmental scale, palpebral disc translucent and divided, tail slightly compressed, all digits clawed, and only six femoral pores (three at each hindlimb) inserted in a clump of small scales. This genus is described as monotypic and only contains Kataphraktosaurus ungerhamiltoni sp. nov., which is known from one specimen and diagnosed by the same set of aforementioned characters. The secretive habits of this species and the remoteness of the locality may explain its singleton situation. Following the International Union for Conservation of Nature’s criteria, we categorized the new species as Data Deficient.

Keywords: Reptilia, Amazonia, biodiversity, Neotropics, Orinoco basin, phylogeny, reptile, systematics, taxonomy

FIGURE 7. Male holotype of Kataphraktosaurus ungerhamiltoni gen. nov., sp. nov. (MHNLS 19960) in life
 (a). Western slope of Serranía del Cuao seen from the Cuao River (b) and Tobogán del Cuao in Caño Bejuco (c), Amazonas state, Venezuela. Photos: F.J.M. Rojas-Runjaic.

Kataphraktosaurus ungerhamiltoni sp. nov.


FIGURE 1. Map of Venezuela indicating the geographic position of Caño Bejuco (yellow pentagon), near Tobogán del Cuao, Autana municipality, Amazonas state, Venezuela, type locality of Kataphraktosaurus ungerhamiltoni gen. nov., sp. nov.

FIGURE 3. Some Cercosaurinae lizards with crocodile-like morphology:
(a) Centrosaura apodema, from La Alfombra, Pérez Zeledón, Costa Rica; (b) Echinosaura brachycephala, from Mindo, Pichincha, Ecuador;
(c) Echinosaura horrida, from Puerto Quito, Pichincha, Ecuador; (d) Gelanesaurus flavogularis, from Archidona, Napo, Ecuador;
(e) Neusticurus arekuna, from Chivatón, Bolívar, Venezuela; (f) Neusticurus medemi, from Las Pavas, Amazonas, Venezuela;
(g) Potamites ecpleopus, from Juami river, Amazonas, Brazil; (h) Potamites erythrocularis, from Inambari, Madre de Dios, Peru.
Photos: C.L. Barrio-Amorós (a–f), F.J.M. Rojas-Runjaic (g), and G. Chávez (h).


Fernando J.M. Rojas-Runjaic, César L. Barrio Amorós, J. Celsa Señaris, Ignacio De la Riva and Santiago Castroviejo-Fisher. 2021. Discovery of An Additional Piece of the Large Gymnophthalmid Puzzle: A New Genus and Species of Stream Spiny Lizard (Squamata: Gymnophthalmidae: Cercosaurinae) from the western Guiana Shield in Venezuela. Zootaxa. 4950(2); 296–320.
DOI: 10.11646/zootaxa.4950.2.4  
Researchgate.net/publication/350471802_a_new_genus_and_species_of_stream_spiny_lizard_from_the_western_Guiana_Shield_in_Venezuela
 twitter.com/RojasRunjaic/status/1376722648785375240


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Sunday, October 4, 2020

[Ichthyology • 2020] Ammoglanis natgeorum • A New Miniature Pencil Catfish (Siluriformes: Trichomycteridae) from the lower Atabapo River, Amazonas, Venezuela


 Ammoglanis natgeorum  
Henschel, Lujan & Baskin, 2020


Abstract
A new species of the sand‐dwelling catfish genus Ammoglanis is described from a marginal habitat of the lower Atabapo River, a left‐bank blackwater tributary of the upper Orinoco River in Amazonas, Venezuela, adjacent to the border with Colombia. Ammoglanis natgeorum is distinguished from all congeners by trunk pigmentation pattern consisting of scattered ventral chromatophores concentrated around the anal‐fin base and numerous additional meristic and anatomical characteristics. A. natgeorum is the second species of Ammoglanis described from the Orinoco River basin after Ammoglanis pulex, and several shared character states (e.g., eight total dorsal‐fin rays, overall coloration pattern and presence of two finger‐like papillae posterior to chin) suggest that it is more closely related to Ammoglanis obliquus (from the central Amazon basin) and A. pulex than to other congeners.

Keywords: blackwater, Orinoco basin, psammophily, riverine infauna, Sarcoglanidinae, taxonomy


Field photos of a live  Ammoglanis natgeorum sp.n. shortly after capture

Ammoglanis natgeorum sp. nov.

Etymology: The specific epithet natgeorum honours the employees of the National Geographic Society (commonly abbreviated as NatGeo), without whose generous support this research would not have been possible. The type specimens were collected during field work funded by National Geographic CRE grant 8721‐09 to NKL, and the first author's research on Ammoglanis and other trichomycterid catfishes has been supported by a NatGeo Early Career Grant.


Elisabeth Henschel, Nathan K. Lujan and Jonathan N. Baskin. 2020. Ammoglanis natgeorum, A New Miniature Pencil Catfish (Siluriformes: Trichomycteridae) from the lower Atabapo River, Amazonas, Venezuela. Journal of Fish Biology. DOI: 10.1111/jfb.14515

    

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Tuesday, August 11, 2020

[Ichthyology • 2020] Curimatopsis sabana • A New Species of Curimatopsis (Characiformes: Curimatidae) from the río Caroni, Orinoco basin, Venezuela, with Comments on C. macrolepis


Curimatopsis sabana 
Melo, 2020


ABSTRACT
A new species of Curimatopsis is described from the highlands of the western Guiana Shield in the río Carapo and río Paragua, tributaries of the río Caroni in the Orinoco basin, southeastern Venezuela. The new species belongs to the Curimatopsis macrolepis clade due to its possession of a long lower jaw that projects past the anterior margin of the upper jaw, and separate first and second hypurals. The new species is diagnosed from remaining species of the Curimatopsis macrolepis clade by having a small-sized inconspicuous dark spot on the midlateral surface of the caudal peduncle, by details of body and fin pigmentation, and by additional morphometric characters. The distribution of C. macrolepis in the Amazon and Orinoco basins is updated based on the examination of museum specimens.

Keywords: Gran Sabana; Guiana Shield; Ostariophysi; Teleostei


FIGURE 1: Curimatopsis sabana, AMNH 274996, holotype, 36.5 mm SL, female, Venezuela, Bolívar, río Paragua, río Caroni, Orinoco basin (top). AUM 36458, paratype, 43.5 mm SL, male, Venezuela, Bolívar, río Paragua, río Caroni, Orinoco basin (bottom).


FIGURE 4: Species of the Curimatopsis macrolepis clade:
A-B) C. macrolepis, LBP 22425, rio Solimões, Letícia, Colombia;
C) C. jaci, female, MZUSP 121197, holotype, rio Cristalino, upper Tapajós basin; D) C. jaci, male, MZUSP 116668, paratype, rio São Benedito, upper Tapajós basin;
E) C. maculosa, LBP 13907, paratype, middle rio Tapajós; F) C. melanura, MPEG 15335, holotype, rio Nhamundá;
G) Curimatopsis sabana, female, AMNH 274996, holotype, río Caroni basin; H) C. sabana, male, AUM 36458, paratype, río Caroni basin.
 Photos by Bruno Melo (A-E, G-H) and Guilherme Dutra (F).


Curimatopsis sabana, new species

Diagnosis. Curimatopsis sabana belongs to the C. macrolepis clade (C. jaci Melo, Oliveira, 2017, C. maculosa Melo, Vari, Oliveira, 2016, C. macrolepis, and C. melanura Dutra, Melo, Netto-Ferreira, 2018) and can be easily diagnosed from species of the C. evelynae clade (C. cryptica Vari, 1982, C. evelynae, C. guaporensis Melo, Oliveira, 2017, C. myersi Vari, 1982, and C. pallida Melo, Oliveira, 2017) by having a longer lower jaw that projects past the anterior margin of the upper jaw (vs. lower jaw shorter and not overlapping the upper jaw), and by separate (vs. fused) first and second hypurals. Within the C. macrolepis clade, C. sabana is diagnosed from C. melanura by the absence (vs. presence) of the dark pigmentation on the entire lower lobe of the caudal fin. It differs from C. jaci by the absence (vs. presence) of a distinctly reticulate color pattern on the flanks of females. It is diagnosed from C. maculosa by the possession of a round spot of black pigmentation, sometimes very faint, on the midlateral surface of the caudal peduncle (vs. a small posteriorly pointed spot overlapping the posterior midlateral scales), by the absence (vs. presence) of a gap of two or three scales separating the pigmentation of the midlateral stripe and the dark spot on caudal peduncle, by a deeper body, 34.1-39.9% of SL (vs. 26.0-31.6% of SL), and deeper caudal peduncle, 13.7-17.4% of SL (vs. 9.0-13.7% of SL). It differs from C. macrolepis by the possession of a circular and weakly pigmented spot on the caudal peduncle (vs. horizontally elongated and strongly pigmented dark spot on caudal peduncle). Finally, it differs from C. microlepis by 26-28 (vs. 57-63) scales in the longitudinal series from the supracleithrum to the hypural joint.

FIGURE 2: Map of northern South America showing the collection localities of species of the Curimatopsis macrolepis clade in the Orinoco and Amazon basins. Note the distribution of Curimatopsis sabana in highlands of the Guiana Shield. T = type locality. 
 
FIGURE 3: Habitat of Curimatopsis sabana, AUM 36458, a drying pool of the río Paragua, tributary of the río Caroni. Photograph by J.W. Armbruster. 


Distribution. Curimatopsis sabana is only known from the Carapo and Paragua rivers, which are tributaries of the río Caroni, itself a right-bank tributary of the río Orinoco basin, in the western Guiana Shield in Venezuela (Fig. 2). Various specimens were collected in the region of the río Carapo, near Cerro Guaiquinima (4 km along the river, 300-310 m asl), and one specimen was collected in a drying pool of the lower río Paragua (272 m asl) (Fig. 3). The distribution suggests that C. sabana is restricted to higher elevations of the western Guiana Shield.

Etymology. The specific name sabana refers to the Gran Sabana, a major ecoregion in the western Guiana Shield of southeastern Venezuela, which encompasses the río Caroni basin. A noun in apposition.


Bruno F. Melo. 2020. New Species of Curimatopsis from the río Caroni, Orinoco basin, Venezuela, with Comments on C. macrolepis (Characiformes: Curimatidae). Neotrop. ichthyol. 18(2). DOI: 10.1590/1982-0224-2020-0002   

RESUMO: Uma nova espécie de Curimatopsis é descrita da porção oeste do Escudo das Guianas dos ríos Carapo e Paragua, tributários do río Caroni, bacia do Orinoco no sudeste da Venezuela. A nova espécie pertence ao clado Curimatopsis macrolepis por possuir uma maxila inferior longa que se projeta além da margem anterior da maxila superior e primeiro e segundo hipurais separados. A nova espécie é diagnosticada das demais espécies do clado Curimatopsis macrolepis por possuir uma mácula escura pequena, inconspícua na superfície lateral do pedúnculo caudal, por detalhes de pigmentação do corpo e nadadeiras, e por dados morfométricos adicionais. A distribuição geográfica de C. macrolepis nas bacias do rio Amazonas e río Orinoco é atualizada baseada na análise de espécimes depositados em museus.
Palavras-chave: Gran Sabana; Escudo das Guianas; Ostariophysi; Teleostei

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Wednesday, April 15, 2020

[Herpetology • 2020] Chelus orinocensis & C. fimbriata • Genomic Analyses reveal Two Species of the Matamata (Testudines: Chelidae: Chelus spp.) and Clarify Their Phylogeography


Chelus orinocensis 
 Vargas-Ramírez, Caballero, Morales-Betancourt, Lasso, Amaya, et al., 2020.

photos: Fernando Trujillo. sostenibilidad.semana.com

Highlights
• Another species of matamata (Chelus orinocensis), one of the most bizarre turtles of the world, is described as new to science.
• Chelus orinocensis differs genetically and morphologically significantly from C. fimbriata.
• The two species diverged in the late Miocene, approximately 13 million years ago.
• Chelus orinocensis occurs in the Orinoco and Río Negro Basins and the Essequibo drainage; C. fimbriata sensu stricto is restricted to the Amazon Basin and the Mahury drainage.
 • Chelus orinocensis possess in the Essequibo and Branco Rivers introgressed haplotypes from C. fimbriata.


Abstract
The matamata is one of the most charismatic turtles on earth, widely distributed in northern South America. Debates have occurred over whether or not there should be two subspecies or species recognized due to its geographic variation in morphology. Even though the matamata is universally known, its natural history, conservation status and biogeography are largely unexplored. In this study we examined the phylogeographic differentiation of the matamata based on three mitochondrial DNA fragments (2168 bp of the control region, cytochrome oxidase subunit I, and the cytochrome b gene), one nuclear genomic DNA fragment (1068 bp of the R35 intron) and 1661 Single Nucleotide Polymorphisms (SNPs). Our molecular and morphological analyses revealed the existence of two distinct, genetically deeply divergent evolutionary lineages of matamatas that separated in the late Miocene (approximately 12.7 million years ago), corresponding well to the time when the Orinoco Basin was established. As a result of our analyses, we describe the genetically and morphologically highly distinct matamata from the Orinoco and Río Negro Basins and the Essequibo drainage as a species new to science (Chelus orinocensis sp. nov.). Chelus fimbriata sensu stricto is distributed in the Amazon Basin and the Mahury drainage. Additionally, the analyses revealed that each species displays phylogeographic differentiation. For C. orinocensis, there is moderate mitochondrial differentiation between the Orinoco and the Río Negro. For C. fimbriata, there is more pronounced differentiation matching different river systems. One mitochondrial clade was identified from the Amazon, Ucayali, and Mahury Rivers, and another one from the Madeira and Jaci Paraná Rivers. The C. orinocensis in the Essequibo and Branco Rivers have haplotypes that constitute a third clade clustering with C. fimbriata. Phylogenetic analyses of the R35 intron and SNP data link the matamatas from the Essequibo and Branco with the new species, suggesting past gene flow and old mitochondrial introgression. Chelus orinocensis is collected for the pet trade in Colombia and Venezuela. However, neither the extent of the harvest nor its impact are known. Hence, it is crucial to gather more information and to assess its exploitation throughout its distribution range to obtain a better understanding of its conservation status and to design appropriate conservation and management procedures.

Keywords: Amazonas, Chelus orinocensis sp. nov., mtDNA, nDNA, Orinoco, South America, Taxonomy




     
photos: Fernando Trujillo. 
 sostenibilidad.semana.com


     

Chelus orinocensis sp. nov.

Etymology: The species name orinocensis is a Latinized adjective and refers to the Orinoco drainage as core distribution of the new species.

 Proposed vernacular names: Orinoco matamata (English), mata-mata do Orinoco (Portuguese), matamata orinocence, matamata del Orinoco, caripatúa (Spanish). The Sikuani indigenous group, native people in the Orinoco region, name this turtle “Atzapani”. 
For Chelus fimbriata the following vernacular names are proposed: Amazon matamata (English), mata-mata amazônica (Portuguese), matamata amazonica, matamata del Amazonas (Spanish).

 Distribution: Chelus orinocensis occurs in the Orinoco Basin and the upper Río Negro (Amazon Basin) in north-western South America, ....

     


Lasso, et al, 2018. DOI: 10.21068/c2018.v19n01a10
twitter.com/CLassoAlcala


      
photos: Fernando Trujillo.
 sostenibilidad.semana.com  


Mario Vargas-Ramírez, Susana Caballero, Mónica A. Morales-Betancourt, Carlos A. Lasso, Laura Amaya, José Gregorio Martínez, Mariadas Neves Silva Viana, Richard C. Vogt, Izeni Pires Farias, Tomas Hrbek, Patrick D. Campbell and Uwe Fritz. 2020. Genomic Analyses reveal Two Species of the Matamata (Testudines: Chelidae: Chelus spp.) and Clarify Their Phylogeography. Molecular Phylogenetics and Evolution. In Press, 106823.  DOI: 10.1016/j.ympev.2020.106823 
twitter.com/CLassoAlcala/status/1043223205152997376

C.A. Lasso, F. Trujillo, M.A. Morales-Betancourt, L. Amaya, S. Caballero, B. Castañeda
Carlos A. Lasso, Fernando Trujillo, Monica A. Morales-Betancourt, Laura Amaya, Susana Caballero and Beiker Castañeda. 2018. Conservación y tráfico de la tortuga matamata, Chelus fimbriata (Schneider, 1783) en Colombia: un ejemplo del trabajo conjunto entre el Sistema Nacional Ambiental
ONG y academia [Conservation and trafficking of the Matamata Turtle, Chelus fimbriata (Schneider, 1783) in Colombia: an example of joint efforts of the National Environmental System, one NGO, and academia]. Biota Colomb. 19(1); 147-159. DOI: 10.21068/c2018.v19n01a10

      

Red de tráfico internacional pone en riesgo a extraña especie de tortuga de la Orinoquia

RESUMEN: La matamata es una de las tortugas más carismáticas del mundo, ampliamente distribuida en el norte de Sudamérica. Debido a su variación morfológica geográfica, se debate sobre el reconocimiento de dos subespecies o especies. A pesar de que la matamata es universalmente conocida, su historia natural, estado de conservación y biogeografía han sido muy poco estudiados. En este estudio examinamos la diferenciación filogeográfica de las matamatas en base ​​a tres fragmentos de ADN mitocondrial (2168 pb de la región de control, la subunidad I del citocromo oxidasa y el gen del citocromo b), un fragmento de ADN genómico nuclear (1068 pb del intrón R35) y 1661 polimorfismos de nucleótido único (SNP). Nuestros análisis moleculares y morfológicos revelaron la existencia de dos linajes evolutivos distintos de matamatas, genéticamente divergentes que se separaron en el Mioceno tardio (hace aproximadamente 12.7 millones de años), correspondiendo al tiempo en que se estableció la cuenca del Orinoco. Como resultado de nuestros análisis, describimos las genéticamente y morfológicamente distintas matamatas de las cuencas del Orinoco, Río Negro y Essequibo como una especie nueva para la ciencia (Chelus orinocensis sp. nov.). Chelus fimbriata sensu stricto se distribuye en la cuenca del Amazonas y en el drenaje del Mahury. Adicionalmente, los análisis revelaron que cada especie muestra diferenciación filogeográfica. Para C. orinocensis, hay una moderada diferenciación mitocondrial entre el Orinoco y el Río Negro. Para C. fimbriata, hay una diferenciación más pronunciada, concordando con los diferentes sistemas fluviales. Se identificó un clado de los ríos Amazonas, Ucayali y Mahury y otro de los ríos Madeira y Jaci Paraná. Las C. orinocensis de los ríos Essequibo y Branco tienen haplotipos que constituyen un tercer clado que se agrupa con C. fimbriata. Los análisis filogenéticos del intrón R35 y los datos de SNP asocian las matamatas de Essequibo y Branco con la nueva especie, sugiriendo flujo de genes pasado ​​e introgresión mitocondrial antigua. Chelus orinocensis se colecta para el comercio de mascotas en Colombia y Venezuela. Sin embargo, ni se conoce el alcance de las colectas ni su impacto. Por lo tanto, es crucial recopilar más información y evaluar su explotación en todo su rango de distribución, comprender mejor su estado de conservación y para diseñar acciones apropiadas de conservación y manejo.

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