earth science

Tonna perdix

Tonna perdix is a earth science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Tonna perdix rather than just read about it. In short: Tonna perdix, common name the partridge tun, is a species of very large sea snail, a marine gastropod mollusc in the family Tonnidae, the tun shells. Description The pattern and brownish colour of the shell is reminiscent of a partridge's plumage hence the common name.

Key takeaways

Tonna perdix belongs to earth science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Tonna perdix to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Tonna perdix from memory before moving on to harder problems.

Reference excerpt

Tonna perdix, common name the partridge tun, is a species of very large sea snail, a marine gastropod mollusc in the family Tonnidae, the tun shells.

Description The pattern and brownish colour of the shell is reminiscent of a partridge's plumage hence the common name. The size of an adult shell varies between 70 mm and 220 mm. The ovate-oblong shell is ventricose and pretty thin. It is of a reddish-brown color, pleasingly varied with white spots in transverse series, for the most part semi-lunar, and more or less distant. The conical spire is slightly projecting and pointed. It is composed of five to six whorls which are furnished with numerous ribs, often widened, feebly convex, and separated by furrows hardly apparent. The suture is very distinct and is slightly channeled towards the body whorl. The aperture is large, subovate, marked by transverse and slightly projecting bands, which correspond to the furrows of the exterior. The interior of this cavity is of a fawn color. The outer lip is thin, everted, a little undulated, and adorned with a white band the whole length of its interior, with the exception of the edge, which is of a deep brown. The inner lip is spread out over the body of the shell. It is very thin, transparent, and terminated below by a projecting plate which covers the umbilicus, and seems also to form a part of it. The columella is smooth, polished, and forms at the left of the umbilicus a thick rib, marked by transverse striae, which terminates at the emargination of the base. The ground color of the shell is a bluish white, covered with irregular spots of a red brown, bordering upon the violet. The foot is colored in the same manner beneath, but above, it is furrowed with wide triangular radiating bands. The tentacles are doubly ringed with brown.

Distribution This species occurs in the Red Sea and in the Indian Ocean off Aldabra, Chagos, Madagascar, the Mascarene Basin, Mauritius and Tanzania, and in the Pacific Ocean off New Zealand, Australia (Northern Territory, Queensland, Western Australia) and the Galapagos Islands. The mollusk of this shell inhabits rapid waters, and appears pretty quick in its movements.

Biology and diet This gastropod is a highly specialized carnivorous predator, preying on sea cucumbers.

References

Bibliography Hedley, C. 1919. A review of the Australian Tun Shells. Records of the Australian Museum 12(11): 329-336, pls 39-44 Dautzenberg, Ph. (1929). Mollusques testacés marins de Madagascar. Faune des Colonies Francaises, Tome III Turner, R.D. 1948. The family Tonnidae in the western Atlantic. Johnsonia: Monographs of the marine mollusks of the Western Atlantic 2(26): 165-192, pl. 74-85 Kilias, R. 1962. Gastropoda/Prosobranchia. Tonnidae. Das Tierreich 77: 1-63 Kay, E.A. 1979. Hawaiian Marine Shells. Reef and shore fauna of Hawaii. Section 4 : Mollusca. Honolulu, Hawaii : Bishop Museum Press Bernice P. Bishop Museum Special Publication Vol. 64(4) 653 pp. Drivas, J. & M. Jay (1988). Coquillages de La Réunion et de l'île Maurice Morton, B. (1991) Aspects of Predation by Tonna zonatum (PROSOBRANCHIA: TONNOIDEA) Feeding on Holothurians in Hong Kong. J. Moll. Stud. (1991), 57, 11-19. Wilson, B. 1993. Australian Marine Shells. Prosobranch Gastropods. Kallaroo, Western Australia : Odyssey Publishing Vol. 1 408 pp. Vos, C. (2007). A conchological Iconography (No. 13) - The family Tonnidae. 123 pp., 30 numb. plus 41 (1 col.) un-numb. text-figs, 33 maps., 63 col. pls, Conchbooks, Germany Vos, C. (2008) Tonnidae. in Poppe G.T. (ed.) Philippine Marine Mollusks, Volume 1: Gastropoda 1: 594-611, pls 242-250. Conchbooks, Hackenheim, Germany. Spencer, H.; Marshall. B. (2009). All Mollusca except Opisthobranchia. In: Gordon, D. (Ed.) (2009). New Zealand Inventory of Biodiversity. Volume One: Kingdom Animalia. 584 pp Beu, A. G. (2005) Neogene fossil tonnoidean gastropods of Indonesia. Scripta Geologica 130, p. 1-186, pp. 166, figs. 327 Beu, A.G., Bouchet, P. & Tröndlé, J. 2012. Tonnoidean gastropods of French Polynesia. Molluscan Research 32(2): 61-120 Cernohorsky. W. O. (1972). Marine Shells of the Pacific. Vol. II. Pacific Publications, Sydney, 411 pp. Steyn, D.G. & Lussi, M. (1998) Marine Shells of South Africa. An Illustrated Collector's Guide to Beached Shells. Ekogilde Publishers, Hartebeespoort, South Africa, ii + 264 pp. Liu, J.Y. [Ruiyu] (ed.). (2008). Checklist of marine biota of China seas. China Science Press. 1267 pp. Steyn, D. G.; Lussi, M. (2005). Offshore Shells of Southern Africa: A pictorial guide to more than 750 Gastropods. Published by the authors. pp. i–vi, 1–289. Vos, C. (2012) Overview of the Tonnidae (MOLLUSCA: GASTROPODA) in Chinese waters. Shell Discoveries 1(1); pp. 12–22; Pls. 1-9 Vos, C. (2013) Overview of the Tonnidae (Mollusca: Gastropoda) in Chinese waters. Gloria Maris 52(1-2); pp. 22–53; Pls. 1-9 Severns, M. (2011). Shells of the Hawaiian Islands - The Sea Shells. Conchbooks, Hackenheim. 564 pp.

External links

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Illustrations

Worked examples

Example 1 — a first encounter with Tonna perdix

Start with the simplest possible case. Write down what Tonna perdix claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In earth science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Tonna perdix before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Tonna perdix ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Tonna perdix

In research: Tonna perdix appears in earth science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Tonna perdix in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Tonna perdix is common in secondary-school and first-year university syllabi. It links to neighbouring topics Animal taxa named by Carl Linnaeus, Gastropods described in 1758, Molluscs of the Indian Ocean, so understanding it makes those chapters shorter.
In everyday life: Look for Tonna perdix outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Tonna perdix in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Tonna perdix means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
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Frequently asked questions

What is Tonna perdix in simple terms?

Tonna perdix, common name the partridge tun, is a species of very large sea snail, a marine gastropod mollusc in the family Tonnidae, the tun shells. Description The pattern and brownish colour of the shell is reminiscent of a partridge's plumage hence the common name.

Why does Tonna perdix matter?

Because it connects several earth science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Tonna perdix?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Tonna perdix.