Kryptoglanis: a catfish mimic

Workers wondered, where did those big teeth come from?
Catfish don’t have such long, interlocking teeth. No wonder Vincent and Thomas 2011 called Kryptoglanis shajii (Figs. 1–3; 6cm) an ‘enigmatic’ subterranean catfish. No wonder Britz et al. erected a new clade of catfish to put it in.

Figure 1. The uncatfish-like teeth of Kryptoglanis in anterior view.

Figure 1. The uncatfish-like teeth of Kryptoglanis in anterior view.

According to Wikipedia
“[Kryptoglanis] has also been seen in dense vegetation in paddy fieldsThe species strongly avoids light and feeds on small invertebrates.”

“The morphology of K. shajii differs from all other known species of catfish and includes such features as the absence of dorsal fin; the presence of four pairs of barbels; an upwardly directed mouth, with a distinctly projecting lower jaw with 4 set[s] of teeth; subcutaneous eyes; anal fin completely confluent with the caudal fin; anal and caudal fins together carry 70–74 fin rays; and no spines in any of the fins.”

Figure 2. Kryptoglanis in 3 views. Note the catfish-like barbels.

Figure 2. Kryptoglanis in 3 views. Note the catfish-like barbels.

Figure 3. Skull of Kryptoglanis, a knife fish, not a catfish.

Figure 3. Skull of Kryptoglanis, a knife fish, not a catfish.

Here’s where we put on our lab coats and act like scientists.
Whenever a taxon is described as ‘differs from all other known species’, that’s the time to expand the taxon list. We’ve seen this so many times before. And every time the LRT has found less traditional and more parsimonious sister taxa simply by adding taxa.

Figure x. Gymnotus carapo in vivo.

Figure 4. Gymnotus carapo in vivo.

Figure 8. Skull of Gymnotus.

Figure 5. Skull of Gymnotus.

According to
the large reptile tree (LRT, 1750+ taxa) those catfish-like barbels on Kryptoglanis developed by convergence on an eel-like knife fish, nesting between the eel, Anguilla and two knifefish, Gymnotus and Electrophorus, the electric eel. This clade of fish DO have large interlocking teeth and a long list of other traits shared with Kryptoglanis. They just don’t have barbels. Seems like prior authors were caught “Pulling a Larry Martin” by focusing on the barbels to the exclusion of all the other traits.

Figure 1. Subset of the LRT focusing on the ray fin only clade of bony fish. Fundulus (yellow) is the new taxon. It attracted Anableps. Various convergent eel-like taxa are shown in baby blue.

Figure 1. Subset of the LRT focusing on the ray fin only clade of bony fish. Fundulus (yellow) is the new taxon. It attracted Anableps. Various convergent eel-like taxa are shown in baby blue.


References
Vincent M and Thomas J 2011. Kryptoglanis shajii, an enigmatic subterranean-spring catfish (Siluriformes, Incertae sedis) from Kerala, India. Ichthyological Research. 58 (2): 161–165. doi:10.1007/s10228-011-0206-6.
Britz R, Kakkassery F and Raghavan R 2014. Osteology of Kryptoglanis shajii, a stygobitic catfish (Teleostei: Siluriformes) from Peninsular India with a diagnosis of the new family Kryptoglanidae. Ichthyological Exploration of Freshwaters. 24 (3): 193–207.

wiki/Kryptoglanis_shajii

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