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Bob Carney

@below500m.bsky.social

LSU Emeritus Professor of Oceanography and Coastal Sciences at LSU, interested in deep-sea megafauna especially holothuroids

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Bob Carney@below500m.bsky.social · 13h ago

Enypniastes' Rolled Branching Trees. ROV tech and skill now permit study of the frantic feeding by miniature multi-trunked flying Dumbos. Identifying the mechanics quickly leads to reiterative bifurcation, fukimodoshi toys and circinate vernation . Soft-robotic adaptations in deep holothuroids.

Enypniastes is a genus of holothuroid especially adapted to existence both on the deep-sea bottom and in the water a few meters above. The baseball-size body has a large anterior fin and paired posterior fins. The former is used for swimming and orientation. The latter also assist in walking and maintaining bottom contact. The shapes of the feeding tentacles reflect the rolling and unrolling of a bifuracting hydrostactic tube system. Sediment bits adhere to sticky tips then release when the tentacle is brought to the mouth. This specimen is a dark opaque purple making shape easy to observe. Fukimodoshi is the Japanese name for "blow out" or "roll out" child's toy. The tentacle branches operate similarly. Circinate vernation refers to the shape of fiddlehead ferns which unroll through the soil. Models of fern growth may help develop digital models of tentacle structure and function. Picture for NOAA-Okeanos Image Archives EX1711_IMG_20171213T182309Z_ROVHD.jpg Laser dots provide a 10cm scale reference.Enypniastes is a genus of holothuroid especially adapted to existence both on the deep-sea bottom and in the water a few meters above. The baseball-size body has a large anterior fin and paired posterior fins. The former is used for swimming and orientation. The latter also assist in walking and maintaining bottom contact. The shapes of the feeding tentacles reflect the rolling and unrolling of a bifuracting hydrostactic tube system. Sediment bits adhere to sticky tips then release when the tentacle is brought to the mouth. This specimen is a light translucent purple low contrast with the sediment make structure more difficult to determine, but internal features are visible. Fukimodoshi is the Japanese name for "blow out" or "roll out" child's toy. The tentacle branches operate similarly. Circinate vernation refers to the shape of fiddlehead ferns which unroll through the soil. Models of fern growth may help develop digital models of tentacle structure and function. Picture for NOAA-Okeanos Image Archives EX1711_IMG_20171213T182309Z_ROVHD.jpg Laser dots provide a 10cm scale reference.
Bob Carney@below500m.bsky.social · 4d ago

Surprise Pelagic Holothuroid, EX2304 Dive 4 from NOAA Okeanos image archives. ~2000m off Aleutians. Approx 5 threadlike tentacles sparsely branched, a larval condition. Sorry, no scale. EX2304_IMG_20230719T014110Z_ROVHD.jpg @noaa.gov

Suspended in a dark blue world, the Rov illuminates a unusual transparent ellipsoid body containing a simple intestine shaped like a coiled spring. Faint water-vascular canals along the length of the body shows that the animal is an Echinoderm. Being worm-like makes it a holothuroid. The 5 simple tentacles are a larval condition. Adult holothuroids have 10 or more.
Bob Carney@below500m.bsky.social · 2w ago

Holothuroid tentacle is more than modified tubefoot! Udagawa et al. excellent larval holo dev study shows that the 5 initial tents are homologous to the 5 water-vascular canals. Modern micro techniques are incredibly informative. https:// doi. org/10. 1038/ s41598- 022- 09691-y

Udagawa and colleagues used modern micro-imaging techniques to track the partial imposition of adult pentaradial symmetry onto the larval bisymmetry. The selected image shows the budding of the anterior left hydrocoel as it encircles the anterior gut, forming a ring. Five initial buds multiply and give rise to feeding tenacles extending out of the body. Five secondary buds grow the length of the body as water-vascular canals that do not multiply but can branch off appendages including tubefeet. Feeding tentacles are often described as being "modified tubefeet". It is more accurate to say that feeding tentacles are modified radial canals. Among echinoderms holothuroids retain a soft body form. Understanding the body symmetry is easiest when the larvae are compared. The upper row of figures shows the position of the transforming hydrocoel within the larva. The lower row shows schematic representations of the hydrocoel budding and forming a ring. Or that radial canals are modified tentacles.
Bob Carney@below500m.bsky.social · 3mo ago

Two ~ 1cm Enypniastes. Left - NOAA Okeanos Expl., in situ, full zoom, Gulf of Mexico. Right- Larry Madin, WHOI, wetlab macro-photo, Sulu Sea. Juveniles in Atl/GoM and Indo/Pac both have 10 tentacles.

Enypniastes is a genus of holothuroids that is modified for an unusual deep-sea existence. They spend only a brief time on bottom rapidly consuming the very top layer of sediment. Then they spend long periods of time a few meters above the bottom swimming, drifting and sinking back to the bottom. Pictured are to juvenile specimens estimated to be about 1 cm across. One is recorded at full zoom from a NOAA Ocean Exploration ROV. The other image was taken onboard a reseach vessel after the animal had been sampled by ROV. The swimming image was obtained through the NOAA Ocean Exploration video portal. Dr Larry Madin of Woods Hole Oceanographic Institution provided the lab image.
Bob Carney@below500m.bsky.social · 4mo ago

Holothuroid tentacles modelled as trees formed by bifurcating tip nodules. Just 3 parameters shift from Psolus sp. (lft) to Holothuria cinerascens (rt). The tips use an stick/release system to gather food. The tentacles are hydrostatic, elastic and flexible. # bifurcation, # Blender, # Holothuroid.

There is a rich history of studying plant branching mathematically. Many of the ideas and methods can be applied to animals that branch. In this post an image shows two types of Holothuroid feeding tentacles simulated using Python scripts and Blender 3D modelling app. Changing just 3 parameters in the model transitions between a tall zig-zag tree that is found in the genus Psolus and a spreading tree sound in the species Holothuria cinerascens. Much of the species diversification seen in holothuroids may reflect minor alterations in a basic system of tube bifurcations. New interest in holothuroid tentacles comes from the large number of excellent images of live animals posted online. The Python scripts and Blender manipulations used in this study are under development in collaboration with the AI agent Gemini
Bob Carney@below500m.bsky.social · last yr.

Listening to a mockingbird sing while the silverbell tree dies. Louisiana rice vodka makes the bird song more joyful but does nothing to make the tree's approaching demise less sorrowful.

Bob Carney@below500m.bsky.social · last yr.

"Why do men, sitting at the microscope, examine the calcareous plates of a sea-cucumber, and, finding a new arrangement and number, feel an exaltation and give the new species a name, and write about it possessively? It would be good to know the impulse truly..." J. Steinbeck & E. Ricketts