Gibbula joubini

Gibbula joubini is a species of sea snail, a marine gastropod mollusk in the family Trochidae, the top snails.[2]

Gibbula joubini
Original drawing with three views of a shell of Gibbula joubini
Scientific classification
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Clade: Vetigastropoda
Order: Trochida
Superfamily: Trochoidea
Family: Trochidae
Genus: Gibbula
Species:
G. joubini
Binomial name
Gibbula joubini
Dautzenberg, 1910[1]

Description

The size of the shell varies between 2 mm and 5 mm. The rather solid shell has a trochiform shape. It is somewhat, but rather deeply, umbilicated. The conoid spire consists of 6½ somewhat convex whorls with a very pronounced suture. The first two whorls are smooth, the other contain decurrent striae, that are rather sharp and projecting. The growth lines are very narrow and only visible under a lens. The body whorl is bluntly angular at the periphery and almost flat below. The base of the shell contains 5 to 7 concentric ribs. The aperture is subquadrangular. The columella is almost vertical and is slightly curved upwards, forming almost a right angle with the rim of the base. The lip is simple and curved. The color of the shell is very variable. The main color is whitish with narrow, decurrent, sometimes interrupted black lines. The surface sometimes contains large, longitudinal, brown flames, curved to the right.[3]

Distribution

This species occurs in the Atlantic Ocean off the Western Sahara and Senegal.

gollark: I would quite like to implement this on osmarks.net using an inbrowser Lua VM.
gollark: ```scheme(define (take n xs) (let loop ((n n) (xs xs) (zs (list))) (if (or (zero? n) (null? xs)) (reverse zs) (loop (- n 1) (cdr xs) (cons (car xs) zs)))))(define (zip . xss) (apply map list xss))(define actually-forgiving-grudge (lambda (x y) (let* ( (defection-count (length (filter (lambda (m) (= m 1)) x))) (lookback (+ 1 (inexact->exact (floor (expt 1.8 defection-count))))) (result (if (member '(1 0) (take lookback (zip x y))) 1 0)) ) result)))```if you want to add it to your stuff.
gollark: Do you like `actually-forgiving-grudge`?!
gollark: https://github.com/cristal-smac/ipd - huh
gollark: > [Edit] Worth to note is that Gradual was designed to be a strategy that outperforms Tit for Tat. It has similar properties in that it is willing to cooperate and retaliates against a defecting opponent. Unlike Tit for Tat, which only has a memory of the last round played, Gradual will remember the complete interaction and defect the number of times the opponent has defected so far. It will offer mutual cooperation afterwards again, though.

References
  1. Dautzenberg, Ph.; Fischer, H. (1910). Contribution à la faune malacologique de l'Afrique occidentale. Actes Soc. Linn. Bordeaux LXIV: 1-174, plates I-IV. World Register of Marine Species, Retrieved 2012-11-23.
  2. Gofas, S. (2012). Gibbula joubini Dautzenberg, 1910. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=549262 on 2012-11-23
  3. Dautzenberg (1910), Contribution à la faune malacologique de l'Afrique occidentale; Bordeaux :Y. Cadoret,1910 Archived 2014-01-27 at the Wayback Machine
  • To Biodiversity Heritage Library (3 publications)
  • To Encyclopedia of Life
  • To World Register of Marine Species
  • "Gibbula joubini". Gastropods.com. Retrieved 16 January 2019.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.