Two living species of coelacanths?

Abstract

During the period of September 1997 through July 1998, two coelacanth fishes were captured off Manado Tua Island, Sulawesi, Indonesia. These specimens were caught almost 10,000 km from the only other known population of living coelacanths, Latimeria chalumnae, near the Comores. The Indonesian fish was described recently as a new species, Latimeria menadoensis, based on morphological differentiation and DNA sequence divergence in fragments of the cytochrome b and 12S rRNA genes. We have obtained the sequence of 4,823 bp of mitochondrial DNA from the same specimen, including the entire genes for cytochrome b, 12S rRNA, 16S rRNA, four tRNAs, and the control region. The sequence is 4.1% different from the published sequence of an animal captured from the Comores, indicating substantial divergence between the Indonesian and Comorean populations. Nine morphological and meristic differences are purported to distinguish L. menadoensis and L. chalumnae, based on comparison of a single specimen of L. menadoensis to a description of five individuals of L. chalumnae from the Comores. A survey of the literature provided data on 4 of the characters used to distinguish L. menadoensis from L. chalumnae from an additional 16 African coelacanths; for all 4 characters, the Indonesian sample was within the range of variation reported for the African specimens. Nonetheless, L. chalumnae and L. menadoensis appear to be separate species based on divergence of mitochondrial DNA.

Genetically distinct coelacanth population off the northern Tanzanian coast

“…The relative rate test does not reject the molecular clock between groups A and B (Table S3), indicating that we can interpolate the divergence times based on other estimates from the literature. The divergence time between the two coelacanth species was estimated in three studies (14)(15)(16) (16). However, the authors were cautious about this older dating because they also found that evolutionary distance and the pattern of nucleotide substitutions between L. chalumnae and L. menadoensis were very similar to those observed between Pan troglodytes and Pan paniscus, divergence of which may not be older than 10 Mya.…”

“…We compared the rates of pair-wise nucleotide substitutions between individuals in populations A and B to those between L. chalumnae and L. menadoensis (Table 2 and Table S4). Because our data fail to reject a molecular clock (Table S3), we estimated the divergence times using the estimates of the substitution rates from sources in the literature (14)(15)(16) (4) proposed that the coelacanth individuals caught or observed off the African mainland were strays. The argument for the "strays hypothesis" is as follows.…”

Divergence of Mitochondrial Dna Is Not Corroborated by Nuclear Dna, Morphology, or Behavior in Drosophila Simulans

“…Pouyaud et al (1999) based the original description of L. menadoensis on ''significant differences'' in morphology and sequence divergence from its Comoros Island relative, L. chalumnae. Holder et al (1999), however, found that significant morphological differences were based on inadequate comparisons of morphology by Pouyaud et al (1999). Nonetheless, Holder et al (1999) concluded that a 4.1% sequence divergence found within 4823 bp of mitochondrial DNA constitutes substantial divergence and, therefore, is indicative of separate species.…”

New parasite in a coprolite of 240 million years, biogeography of fossil coelacanths, and the influence of air pollutants in a coastal area of northeastern Brazil

“…This group of lobe-finned fishes is presently represented by only two species found in the coastline of the Indian Ocean and Indonesia (Holder et al 1999), but in deep time they showed quite some diversity (Johanson et al 2006, Miguel et al 2014. Raphael Miguel (Universidade do Estado do Rio de Janeiro) and colleagues have reviewed the distribution of the extinct coelacanth group called Mawsoniidae.…”