Anaconda, Rivas & Quintana & Mancuso & Pacheco & Rivas & Mariotto & Salazar-Valenzuela & Baihua & Baihua & Burghardt & Vonk & Hernandez & García-Pérez & Fry & Corey-Rivas, 2024

Rivas, Jesús A., Quintana, Paola De La, Mancuso, Marco, Pacheco, Luis F., Rivas, Gilson A., Mariotto, Sandra, Salazar-Valenzuela, David, Baihua, Marcelo Tepeña, Baihua, Penti, Burghardt, Gordon M., Vonk, Freek J., Hernandez, Emil, García-Pérez, Juán Elías, Fry, Bryan G. & Corey-Rivas, Sarah, 2024, Disentangling the Anacondas: Revealing a New Green Species and Rethinking Yellows, Diversity 16 (127), pp. 1-28 : 16-18

4.2. A New Species of Green Anaconda

Our data show that two distinct lineages within the former E. murinus form well-supported deep clades, allowing the separation of two species based on their genetic divergence, time divergence, and branchlength in both the Bayesian analysis and Maximum Likelihood trees: E. akayima sp. nov. and E. murinus . Although we are aware that our data come only from mitochondrial DNA, the divergence of these clades is substantial. Male and female anacondas have comparable dispersal patterns, showing strong philopatry in both sexes [ 22]; therefore, it is unlikely that the structure found in mDNA is the result of differential dispersal of males and females within the same species. We believe that the lack of support from nuclear genes for the separation of these clades is due to the low rate of variation at these loci, rather than a lack of separation between taxa. We also examined TATA-binding protein ( TBP) and intron data, which also failed to distinguish the northern and southern clades. It separates E. murinus from E. notaeus with an extremely short branch length and a difference of one pair of bases. If two clades that separated at 24 Mya ( Table 5 , Figure 4 ) show such a small difference ( Figure S2 ), it stands to reason that this marker would not be able to detect a split that occurred at 10 Mya. Thus, the lack of nuclear support is more likely to be related to inappropriate markers than to a lack of difference. The mitochondrial support for the separation of these two clades is superior to that found in other vertebrates in the recent literature [ 95, 96].

In addition to the strong mitochondrial DNA support, there is a well-established pattern of the presence of sister species with northern and southern distributions on the continent. These include lizards of the genus Tupinambis , with T. cryptus occupying a distribution similar to the northern species and other species in the south [ 97]; Dracaena , with D. guianensis in the north and D. paraguayensis in the south [ 98, 99]; matamata turtles with Chelus orinocensis in the north and C. fimbriata in the south [ 100]; Red-headed Amazon River turtles ( Podocnemis erythrocephala ) [ 101]; the arboreal boas Corallus with C. ruschenbergerii in the north and others to the south [ 102, 103]; boas of the genus Epicrates with E. maurus in the north and the other lineages in the south [ 104]. While there may not be a clear barrier separating the northern clades from the southern species today, these patterns likely speak to paleogeographic events that produced this split at the continental scale in a variety of taxa (see below). Thus, the separation of E. akayima sp. nov. from E. murinus is not unique and is likely part of this continent-wide biogeographic pattern.

The first challenge in describing this new species of Green Anaconda is to determine which is the new species. In his 1758 Systema Naturae, Linnaeus gave only “America” as the place of origin [ 91]. The Adolphi Friderici Museum has a specimen labelled NRM 9, identified as Boa murina , which could be the specimen described by Linnaeus. The record of this specimen is unclear and there is no provenance for it, but it appears to be a specimen in Linnaeus’ collection and its scale number matches that of # 319 in Linnaeus’ Systema Naturae. Attempts to obtain tissue samples from this specimen were unsuccessful, which is to be expected given the low probability of obtaining usable DNA from such an old, formalin-fixed specimen. It is likely that the specimen described by Linnaeus was from Suriname, as much of the trade to Europe came from this area (E. Åhlander pers. comm.). However, our data show that French Guiana is probably a contact zone where both species can be found, and Suriname may also be a contact zone. Therefore, even if we knew for sure that specimen # 319 in Linnaeus’ collection was from Suriname, we would still not know which species it was, because both species are truly cryptic, and there is no way to tell from morphological data which species the type belongs to, as far as anyone can tell. When Linnaeus described the Boa murina , he provided reference to other specimens from Seba [ 105] and Gronovious [ 92], who in turn cited two specimens by Seba and added his description of a third specimen. The plate 29 specimen cited by Linnaeus has no source in Seba’s catalogue. Gronovius refers to this specimen in one of his entries, entry 44, and also to specimen 1 from plate 23 of Seba’s catalogue. This snake, whose drawing resembles that of E. deschauenseei , has a source, Guianensis, which probably refers to present-day French Guiana. As there is no scale number on either of Seba’s specimens, it is uncertain whether Linnaeus ever examined the specimens himself, or whether he simply based his inclusion of these specimens on the drawings in Seba’s catalogue. Seba’s second collection was sold at auction after his death [ 106] and is probably lost. Gronovious also provides a description of a specimen of his own and alludes to specimen Ain plate 606 of Physica Sacra [ 107]. This specimen is doubtlessly an anaconda that was in the collection of Johann Heinrich Linck, Leipzig. However, there is no type specimen of anacondas in this collection today (Bauer, per com).

Since the provenance of specimen NRM 9 is unknown, and given that both Green Anaconda species are truly cryptic, there is no way to determine which clade the syntypes belong to other than genotyping, which is not possible with such an old specimen. We propose to name E. murinus as the southern species because of its larger distribution and for historical reasons. We believe that naming the new species as the one with the smallest distribution will contribute to the stability of the nomenclature code, as it will result in less geographical change. In addition, although E. akayima sp. nov. is found in French Guiana and Suriname, it is a species of the Orinoco Basin, which was not explored by European naturalists until later. The lectotype for E. murinus is a specimen from the Xingu River in Para, Brazil, labelled MPEG 27,428 in the Museu Paraense Emílio Goeldi. It was found in Altamira, State of Para, Brazil (3 ◦ 9 ′ 16 ′′ S, 52 ◦ 14 ′ 11 ′′ W) in October 2011 by Emil Hernández. Since most of the distribution of E. murinus is in Brazil, we consider it appropriate that the lectotype is in that country, even though the original specimen may have been collected in Suriname. We also designate specimen MCNG 1042 from UNELLEZ Museo de Ciencias Naturales, Venezuela, as the holotype for E. akayima sp. nov. This specimen was collected by Jesús Rivas in March 1993 at Hato El Cedral , Apure Estate, Venezuela (7 ◦ 25 ′ 0.4 ′′ N, 69 ◦ 19 ′ 51 ′′ W) . The diagnostic features of this species, which are morphologically cryptic, required DNA sequencing. We also designate a paratype for E. akayima sp. nov. specimen RMNH.RENA.20768 deposited in the Naturalis Biodiversity Center in the Netherlands and MBUCV 7189 located at the Museo the Biología de la Universidad Central de Venezuela . Information for other type specimens can be found in Table S3 .

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 a kayima/okoyimo/okoimo, in which a kayi / 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. Communication [52]). The species name akayima is pronounced as follows: ekeyime 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 [ 108]. 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 [ 109]. 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 [ 110]. However, all of these differences have been found to be inconsistent [ 24, 27, 111]; 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 asvalid; so, akayima isclearlytheseniorsynonym. Thisis, admittedly, anunorthodox position regarding the International Code of Zoological Nomenclature [ 112], 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.

Figures

Figure 2. Bayesian consensus phylogram for Eunectes species (50% majority-rule consensus tree) using the mtDNA gene sequence dataset (ND2, ND4, Cytb). Bayesian posterior probability node support values> 0.95 are indicated with black circles and distal values are not shown. Refer to Table S1 for details on tip labels.

Figure 4. Calibrated species tree depicting inferred lineage splits, assuming the scenario of one land bridge. Node bars on the tree represent the 95% highest posterior density (HPD95%) divergence interval of each node. Legend at the top shows the split of the E. akayima and E. murinus under the three other scenarios that we tested for.