''Aspidodiadema jacobyi'' is a small

sea urchin Sea urchins () are spiny, globular echinoderms in the class Echinoidea. About 950 species of sea urchin live on the seabed of every ocean and inhabit every depth zone from the intertidal seashore down to . The spherical, hard shells (tests) of ...

in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Aspidodiadematidae The Aspidodiadematidae are a family of sea urchins. Characteristics All the members of the two extant genera, ''Aspidodiadema'' and ''Plesiodiadema'', are found in tropical seas at bathyal and abyssal depths, often on the submarine slopes of i ...

. It lives in tropical seas at great depths. Aspidodiadema jacobyi was first scientifically described in 1880 by

Alexander Emanuel Agassiz Alexander Emmanuel Rodolphe Agassiz (December 17, 1835March 27, 1910), son of Louis Agassiz and stepson of Elizabeth Cabot Agassiz, was an American scientist and engineer. Biography Agassiz was born in Neuchâtel, Switzerland and immigrated t ...

, an American scientist.

Description

''Aspidodiadema jacobyi'' has a globular hard

test Test(s), testing, or TEST may refer to: * Test (assessment), an educational assessment intended to measure the respondents' knowledge or other abilities Arts and entertainment * ''Test'' (2013 film), an American film * ''Test'' (2014 film), ...

or shell protecting the inner organs. The mouth has 10 buccal plates and small rounded buccal notches and is on the oral (bottom) surface which is slightly flattened. The aboral (top) surface has a small coronal ring of tubercles surrounding the anus. The test is composed of 5 radial

ambulacral Ambulacral is a term typically used in the context of anatomical parts of the phylum Echinodermata or class Sea star, Asteroidea and Edrioasteroidea. Echinoderms can have ambulacral parts that include Ossicle (echinoderm), ossicles, plates, spines ...

sets of 3 plates, separated by 5 ambulacral grooves. There are rows of pairs of pores between the ambulacral areas through which the

tube feet Tube feet (technically podia) are small active tubular projections on the oral face of an echinoderm, whether the arms of a starfish, or the undersides of sea urchins, sand dollars and sea cucumbers; they are more discreet though present on britt ...

protrude. Every third row of plates is larger than the other 2 and has a zig-zag row of large primary

tubercle In anatomy, a tubercle (literally 'small tuber', Latin for 'lump') is any round nodule, small eminence, or warty outgrowth found on external or internal organs of a plant or an animal. In plants A tubercle is generally a wart-like projection ...

s. This row does not extend quite as far as the other 2 rows of plates which have similar primary tubercles set serially in a straight line. These large tubercles are perforate and crenulate. There are smaller, secondary tubercles at the edge of the plates. Slender, flexible spines articulate with all these tubercles. These spines are hollow and have bridging structures across their

lumina Lumina may refer to: Arts, entertainment, and media Literature * ''Lumina'', a literary journal published by Sarah Lawrence College * ''World of Lumina'' or ''Lumina'', a graphic novel by Emanuele Tenderini and Linda Cavallini Music * "Lumina", ...

with minute needle-like pillars. The test has green tubercles with purple interambulacral areas.''Aspidodiadema'' A. Agassiz, 1878
London:

Natural History Museum A natural history museum or museum of natural history is a scientific institution with natural history collections that include current and historical records of animals, plants, fungi, ecosystems, geology, paleontology, climatology, and more. ...

. Retrieved 2012-03-04.

Distribution

''Aspidodiadema jacobyi'' is found in the

bathyal zone The bathypelagic zone or bathyal zone (from Greek βαθύς (bathýs), deep) is the part of the open ocean that extends from a depth of below the ocean surface. It lies between the mesopelagic above, and the abyssopelagic below. The bathypelagi ...

at depths of over in the

Caribbean Sea The Caribbean Sea ( es, Mar Caribe; french: Mer des Caraïbes; ht, Lanmè Karayib; jam, Kiaribiyan Sii; nl, Caraïbische Zee; pap, Laman Karibe) is a sea of the Atlantic Ocean in the tropics of the Western Hemisphere. It is bounded by Mexico ...

and

Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an oceanic basin, ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of ...

. Its range extends from the

Bahamas The Bahamas (), officially the Commonwealth of The Bahamas, is an island country within the Lucayan Archipelago of the West Indies in the Atlantic Ocean, North Atlantic. It takes up 97% of the Lucayan Archipelago's land area and is home to ...

and

West Indies The West Indies is a subregion of North America, surrounded by the North Atlantic Ocean and the Caribbean Sea that includes 13 independent island countries and 18 dependencies and other territories in three major archipelagos: the Greater A ...

Colombia Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Car ...

Nicaragua Nicaragua (; ), officially the Republic of Nicaragua (), is the largest country in Central America, bordered by Honduras to the north, the Caribbean to the east, Costa Rica to the south, and the Pacific Ocean to the west. Managua is the cou ...

and

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

Biology

Little was known about the reproductive biology of deep-water sea urchins, therefore a study was undertaken using ''Aspidodiadema jacobyi'' as a model. This species is

dioecious Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproductio ...

with individuals being either male or female. Mature individuals were gathered during the spring on a number of occasions spanning several years. They were collected in the Bahamas by suction at depths of and were kept in containers in the laboratory. Attempts were made to initiate

spawning Spawn is the eggs and sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of releasing the eggs and sperm, and the act of both sexes is called spawning. Most aquatic animals, except for aquati ...

but these were successful on only two occasions. The eggs measured 94–100μm and had a yolk so that newly hatched larvae do not need to feed at first. It was suggested that in the open sea this would allow the larvae to disperse in ocean currents, surviving in cold waters where little food is available. Alternatively, another study found that the eggs are surrounded by

mucous Mucus ( ) is a slippery aqueous secretion produced by, and covering, mucous membranes. It is typically produced from cells found in mucous glands, although it may also originate from mixed glands, which contain both serous and mucous cells. It is ...

through which the sperm, which have unusually elongated heads, must penetrate. The eggs clump together and may adhere in a viscous mass to the adult's spines and be brooded there. The sperm also form a mucous mass, and it may be that a form of pseudo-copulation takes place with the pressing together of the gamete masses of adjacent individuals. In the laboratory, embryos developed over a period of 5 months into echinopluteus larvae measuring over 3000μm which were fed on unicellular algae. During their early stages the larvae developed 2 and then 4 larval arms before the mouth developed at about 11 days. Three further pairs of long arms developed over the next 30 days, after which a posterior process and a ciliated ring appeared successively. At 75 days a rudimentary echinus appeared and at 116 days, podia were apparent. None of the larvae completed

metamorphosis Metamorphosis is a biological process by which an animal physically develops including birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation. Some inse ...

into a juvenile and it was suggested that this may have been because the process needed to be initiated by chemical stimuli that were absent in this

in vitro ''In vitro'' (meaning in glass, or ''in the glass'') studies are performed with microorganisms, cells, or biological molecules outside their normal biological context. Colloquially called "test-tube experiments", these studies in biology an ...

experiment.

References

{{Taxonbar, from=Q2126418 jacobyi Animals described in 1880