The climbing gourami, Anabas: now a flatfish ancestor in the LRT
How and why flatfish became flatfish
was resolved and hypothesized by Friedman 2008 with a description of early Eocene Heteronectes (Figs 1,2) found in France. Note the asymmetric skull (Fig 2) with eyes beginning to migrate to the right side, which is slowly becoming a new dorsal surface.
Figure 3. Heteronectes is transitional between Polydactylus and flatfish.
” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2019/09/heteronectes-chaneti588.jpg?w=300″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2019/09/heteronectes-chaneti588.jpg?w=584″ class=”size-full wp-image-39221″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2019/09/heteronectes-chaneti588.jpg” alt=”Figure 3. Heteronectes is transitional between Polydactylus and flatfish.” width=”584″ height=”252″ srcset=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2019/09/heteronectes-chaneti588.jpg?w=584&h=252 584w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2019/09/heteronectes-chaneti588.jpg?w=150&h=65 150w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2019/09/heteronectes-chaneti588.jpg?w=300&h=130 300w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2019/09/heteronectes-chaneti588.jpg 588w” sizes=”(max-width: 584px) 100vw, 584px” />
Figure 1. Heteronectes is transitional between Polydactylus and flatfish.
Now the question is
which taxon is the proximal outgroup to Heteronectes and the more derived flatfish?
Flatfish range in size from 4 inches to 7 feet in length.
Figure 1. Heteronectes is a basal flatfish, ancestral to flounders, turbots and kin.
” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/07/heteronectes-chaneti_left_right_recon588.jpg?w=263″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/07/heteronectes-chaneti_left_right_recon588.jpg?w=584″ class=”size-full wp-image-93597″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/07/heteronectes-chaneti_left_right_recon588.jpg” alt=”Figure 1. Heteronectes is a basal flatfish, ancestral to flounders, turbots and kin.” width=”584″ height=”667″ srcset=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/07/heteronectes-chaneti_left_right_recon588.jpg?w=584&h=667 584w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/07/heteronectes-chaneti_left_right_recon588.jpg?w=131&h=150 131w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/07/heteronectes-chaneti_left_right_recon588.jpg?w=263&h=300 263w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/07/heteronectes-chaneti_left_right_recon588.jpg 588w” sizes=”(max-width: 584px) 100vw, 584px” />
Figure 2. Heteronectes is a basal flatfish, ancestral to flounders, turbots and kin.
Presently
in the large reptile tree (LRT, 2338 taxa), the climbing gourami, Anabas (Fig 3) is that ancestor/outgroup taxon. Gouramis are members of the perch family with freshwater and marine representatives.
Note: There is no claim here that flop-walking on land preceded flopping onto one side underwater. Anabas has had millions of years to evolve into a semi-terrestrial taxon. A last common ancestor, perhaps from the Mesozoic, would have been a better ancestor.
Figure 1. Anabas, the climbing gourami in vivo and skull diagram. DGS colors added here.
” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/06/anabas.skull588.jpg?w=300″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/06/anabas.skull588.jpg?w=584″ class=”size-full wp-image-93595″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/06/anabas.skull588.jpg” alt=”Figure 1. Anabas, the climbing gourami in vivo and skull diagram. DGS colors added here. ” width=”584″ height=”411″ srcset=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/06/anabas.skull588.jpg?w=584&h=411 584w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/06/anabas.skull588.jpg?w=150&h=106 150w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/06/anabas.skull588.jpg?w=300&h=211 300w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/06/anabas.skull588.jpg 588w” sizes=”(max-width: 584px) 100vw, 584px” />
Figure 3. Anabas, the climbing gourami in vivo and skull diagram. DGS colors added herehttps://en.wikipedia.org/wiki/Climbing_gouram
Harrington et al 2016
reported Polydactylus (Fig 4) was a proximal outgroup taxon to flatfish.
Figure 4. Polydactylus was recovered as a flatfish ancestor by Harrington et al 2014.
” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/07/polydactylus_skull588.jpg?w=268″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/07/polydactylus_skull588.jpg?w=584″ class=”size-full wp-image-93603″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/07/polydactylus_skull588.jpg” alt=”Figure 4. Polydactylus was recovered as a flatfish ancestor by Harrington et al 2014.” width=”584″ height=”655″ srcset=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/07/polydactylus_skull588.jpg?w=584&h=655 584w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/07/polydactylus_skull588.jpg?w=134&h=150 134w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/07/polydactylus_skull588.jpg?w=268&h=300 268w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/07/polydactylus_skull588.jpg 588w” sizes=”(max-width: 584px) 100vw, 584px” />
Figure 4. Polydactylus was recovered as a flatfish ancestor by Harrington et al 2014.
Friedman recovered
Scorpis (Fig 5, 6) as a proximal outgroup to the flatfish including Heteronectes. Wikipedia reported, “Friedman suggested that Heteronectes and Amphistium did not rest completely on the sea floor like modern flatfishes. Instead, they might have only held their tail to the sea floor and kept their head lifted into the water above, using one eye to watch for predators, while the other was used to look for prey in the mud below.“
Figure 5. Flatfish cladogram from Friedman et al 2006.
” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/07/flatfish_evo.gif?w=300″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/07/flatfish_evo.gif?w=584″ class=”size-full wp-image-93606″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/07/flatfish_evo.gif” alt=”Figure 5. Flatfish cladogram from Friedman et al 2006.” width=”584″ height=”447″ srcset=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/07/flatfish_evo.gif?w=584&h=447 584w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/07/flatfish_evo.gif?w=150&h=115 150w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/07/flatfish_evo.gif?w=300&h=230 300w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/07/flatfish_evo.gif?w=768&h=588 768w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/07/flatfish_evo.gif 822w” sizes=”(max-width: 584px) 100vw, 584px” />
Figure 5. Flatfish cladogram from Friedman et al 2008.
Note the flat cranium
on Heteronectes, despite the asymmetric torsion of the eyeballs. Scorpis has a large sagittal crest. Polydactylus (Fig 4) has a similar crest, though the two are unrelated in the LRT.
Figure 2. Scorpis skull from Gregory 1938. Colors added here. No asymmetry is present on this outgroup to the flatfish and Moorish idol.
” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/07/scorpis_skull588.jpg?w=240″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/07/scorpis_skull588.jpg?w=584″ class=”size-full wp-image-93608″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/07/scorpis_skull588.jpg” alt=”Figure 2. Scorpis skull from Gregory 1938. Colors added here. No asymmetry is present on this outgroup to the flatfish and Moorish idol.” width=”584″ height=”729″ srcset=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/07/scorpis_skull588.jpg?w=584&h=729 584w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/07/scorpis_skull588.jpg?w=120&h=150 120w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/07/scorpis_skull588.jpg?w=240&h=300 240w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/07/scorpis_skull588.jpg 588w” sizes=”(max-width: 584px) 100vw, 584px” />
Figure 6. Scorpis skull from Gregory 1938. Colors added here. No asymmetry is present on this outgroup to the flatfish and Moorish idol.
Try as it might to flip flop on land
Anabas has a difficult time maintaining its tall narrow cross-section erect enough to employ its lateral ray fins to progress through mud and matted undergrowth. Nevertheless, it succeeds! You have to admire its spirit and drive!
Here’s a YouTube video link.
On the other hand,
flatfish are sedentary, sit and wait predators – the opposite of climbing gouramis. You have to admire their lack of spirit and drive!
Here’s a YouTube video link.
This appears to be a novel hypothesis of interrelationships.
If not, please provide a citation so I can promote it here.
References
Friedman M 2008. The evolutionary origin of flatfish asymmetry. Nature 454:209–212.
Friedman M 2012. Osteology of †Heteronectes chaneti (Acanthomorpha, Pleuronectiformes), an Eocene stem flatfish, with a discussion of flatfish sister-group relationships. Journal of Vertebrate Paleontology (32) 4: 735-756; doi: 10.1080/02724634.2012.661352
Harrington RC, et al. (6 co-authors) 2016. Phylogenomic analysis of carangimorph fishes reveals flatfish asymmetry arose in a blink of the evolutionary eye. BMC Evolutionary Biology 16 (224).
wiki/Spiny_turbot
wiki/Flatfish
wiki/Hippoglossus
wiki/Atlantic_threadfin
wiki/Heteronectes
Source: https://pterosaurheresies.wordpress.com/2025/07/10/the-climbing-gourami-anabas-now-a-flatfish-ancestor-in-the-lrt/
Anyone can join.
Anyone can contribute.
Anyone can become informed about their world.
"United We Stand" Click Here To Create Your Personal Citizen Journalist Account Today, Be Sure To Invite Your Friends.
Before It’s News® is a community of individuals who report on what’s going on around them, from all around the world. Anyone can join. Anyone can contribute. Anyone can become informed about their world. "United We Stand" Click Here To Create Your Personal Citizen Journalist Account Today, Be Sure To Invite Your Friends.
LION'S MANE PRODUCT
Try Our Lion’s Mane WHOLE MIND Nootropic Blend 60 Capsules
Mushrooms are having a moment. One fabulous fungus in particular, lion’s mane, may help improve memory, depression and anxiety symptoms. They are also an excellent source of nutrients that show promise as a therapy for dementia, and other neurodegenerative diseases. If you’re living with anxiety or depression, you may be curious about all the therapy options out there — including the natural ones.Our Lion’s Mane WHOLE MIND Nootropic Blend has been formulated to utilize the potency of Lion’s mane but also include the benefits of four other Highly Beneficial Mushrooms. Synergistically, they work together to Build your health through improving cognitive function and immunity regardless of your age. Our Nootropic not only improves your Cognitive Function and Activates your Immune System, but it benefits growth of Essential Gut Flora, further enhancing your Vitality.
Our Formula includes: Lion’s Mane Mushrooms which Increase Brain Power through nerve growth, lessen anxiety, reduce depression, and improve concentration. Its an excellent adaptogen, promotes sleep and improves immunity. Shiitake Mushrooms which Fight cancer cells and infectious disease, boost the immune system, promotes brain function, and serves as a source of B vitamins. Maitake Mushrooms which regulate blood sugar levels of diabetics, reduce hypertension and boosts the immune system. Reishi Mushrooms which Fight inflammation, liver disease, fatigue, tumor growth and cancer. They Improve skin disorders and soothes digestive problems, stomach ulcers and leaky gut syndrome. Chaga Mushrooms which have anti-aging effects, boost immune function, improve stamina and athletic performance, even act as a natural aphrodisiac, fighting diabetes and improving liver function. Try Our Lion’s Mane WHOLE MIND Nootropic Blend 60 Capsules Today. Be 100% Satisfied or Receive a Full Money Back Guarantee. Order Yours Today by Following This Link.
| Visits: | 1,708,582,853 |
| Stories: | 8,450,744 |
Whistler Blowers, Insiders
