Saturday, August 22, 2020

Crowned fisherfolk

Worms. It's too general a word, covering everything from a common garden earthworm to a variety of parasites, to flatworms and ribbon worms and scaleworms; to hunters and builders and diggers and tentacled fisherfolk.

The feather duster worms are polychaete worms, segmented worms (like earthworms) but with bristly paddles extending from each segment. They build long tubes to live in, rubbery tubes. (Other polychaete tubeworms make calcareous tubes.) And they have a crown, a bilobed cluster of feathery radioles that opens up at the mouth of the tube, and may have up to several hundred pairs of these radioles. These capture floating particles, sorting them into food or construction material. Near the base of each radiole, they have an eye, a light-sensitive spot that enables them to detect movement nearby, and retract the crown into the tube. The crown may be almost any colour: red, blue, purple, green, tan, pink, orange; solid coloured or striped.

In an angle between two floats, these feather dusters spread their crowns out into the sunlight. In the shade, they all look blackish.

Assorted feather dusters, purple, mauve, tan, maroon. The spiky thing near the upper right is a sea urchin.

Other animals settle on the tubes. Here, tunicates, sponges, algae or hydroids.


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Los gusanos: la palabra abarca demasiados animales, desde la lombriz que vive entre las raices en nuestros jardines, hasta las orugas que se van a hacer mariposas, pasando por una gran variedad de anélidos, platelmintos, poliquetos, etcétera.

Los plumeros de mar son "gusanos" marinos poliquetos; o sea, que están formados de una serie de segmentos, cada uno con par de "patas" o parápodos, estos cubiertos de setas. Se construyen largos tubos flexibles, como de hule. (Otros poliquetos que viven en tubos los hacen a base de carbonato de calcio.) Y llevan una corona, un plumero con radioles (como tentáculos cada uno con sus ramitas). Estos radioles capturan partículas flotantes, dirigiéndolas al uso apropriado, sea comida o material de construcción. Y cerca de la base de cada radiole, tienen un ojito que puede distinguir cambios en el nivel de luz y advertir al plumero a tiempo de esconderse dentro del tubo. Las coronas pueden venir en una gran variedad de colores: morado, azul, rojo, cafe, crema, color de rosa, verde: de un color sólido o con rayas o espirales.

Estos estaban en un ángulo entre dos flotadores, donde les pegaba el sol. En la sombra se ven casi negros.

Otros animalitos se congregan en los tubos: aquí hay tunicados, esponjas, y algas o tal vez hidroides.



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