Evolution News: A Remarkably Candid Statement About an Unsolved Evolutionary Puzzle

Here’s a thought to kick around: The purpose of the category of Deuterostomes may simply be to appear to support a narrative. How many people will really ask for evidence as to whether it does or not?

Evolution News: A Remarkably Candid Statement About an Unsolved Evolutionary Puzzle

About deuterostomes:

According to current systematic theory, everyone reading this right now belongs to the taxonomic category Deuterostomia. This refers to the “second opening”: the group was originally defined with respect to the embryological appearance of the anus (first opening) versus mouth (second opening), a trait no longer considered diagnostic. Deuterostomia is still around as a systematic grouping, however, and it is showing signs of strain. At present, three phyla belong to Deuterostomia: chordates (that’s you), echinoderms (e.g., sea urchins), and hemichordates (acorn worms).

The origins of Deuterostomia represent a long-standing mystery: … – (Paul Nelson, February 21, 2023)

Paul Nelson quotes from a new paper in Biological Reviews:

In many ways, despite hundreds of years of zoological effort and two decades since the publication of the new animal phylogeny (Halanych et al., 1995; Aguinaldo et al., 1997), we remain in an intellectual wild west with regard to deuterostome origins. No hypothesis, no matter how far-fetched it may seem, can be entirely discarded. No theory, no matter how enticingly logical, can claim to have emerged victorious among its competitors. The deuterostomes continue to elude a single, clean narrative to describe their early evolution, a state that is both fascinating and frustrating in equal measure.

and asks, “at what point does the category Deuterostomia become unreal?”

Here’s a thought to kick around: The purpose of the category of Deuterostomes may simply be to appear to support a narrative. How many people will really ask for evidence as to whether it does or not?

The paper requires a fee or subscription.

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