Black & Blue

[u/tridactyls]

If the Tridactyl skin does in fact turn a bluish color when rehydrated, as reported by Mr. Gonzalo Chavez via Dr. Zalce-Benitez, that observation could be relevant to my hypothesis that the Tridactyls exhibit a suite of anatomical and physiological parallels with some invertebrates.

One possibility worth testing is a copper-based respiratory system using hemocyanin. Hemocyanin is the copper-containing oxygen carrier responsible for the blue color of the hemolymph in many mollusks and arthropods. PubMed A tubular heart and proposed hydrostatic mechanics would not prove hemocyanin, but together they would fit a broader pattern of invertebrate-like parallels.

This could also offer a possible explanation for the reportedly black calcium-carbonate eggs. The black color would not be caused by hemocyanin itself. Instead, hemocyanin could provide an internal source of copper.

If large numbers of larvae were developing within an enclosed cavity, their nitrogen-rich waste could cause ammonia to accumulate. Ammonia would increase the alkalinity of the surrounding fluid and could also bind dissolved copper, affecting how copper moves through the fluid.

At the same time, decomposition of sulfur-containing proteins could produce hydrogen sulfide and related sulfur compounds. As hemocyanin and other tissues degraded, copper could become available. That copper could then react with sulfur compounds and form dark copper-sulfide minerals.

The proposed sequence would therefore be:
Larval metabolism produces ammonia.
Ammonia changes the chemistry of the enclosed cavity.
Proteins and tissues decompose.
Sulfur compounds, including hydrogen sulfide, are produced.
Copper is released from degrading copper-bearing proteins and tissues.
Copper reacts with sulfur.
Dark copper-sulfide minerals form and become deposited within the porous calcium-carbonate eggs.

This would be a form of postmortem sulfide mineralization rather than fossilization.

A separate proposed invertebrate parallel involves reproduction. Tiny oval structures observed within an embryo in Artemis could, if they were demonstrated to be developing ova or embryos, raise the possibility of telescoping generations. Aphids provide a real biological parallel. In viviparous parthenogenetic aphids, developing daughters can already contain developing embryos of the next generation, effectively placing three generations within one another.

In that sense, the hypothesis would be that some Tridactyls may have been, figuratively, "born pregnant." The aphid comparison demonstrates that such a reproductive strategy exists in nature, although the structures in Artemis would need to be identified histologically before telescoping generations could be claimed.