''Aegires albopunctatus'', commonly known as the salt-and-pepper doris, is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

sea slug Sea slug is a common name for some Marine biology, marine invertebrates with varying levels of resemblance to terrestrial Slug, slugs. Most creatures known as sea slugs are gastropods, i.e. they are Sea snail, sea snails (marine gastropod moll ...

nudibranch Nudibranchs () are a group of soft-bodied marine gastropod molluscs, belonging to the order Nudibranchia, that shed their shells after their larval stage. They are noted for their often extraordinary colours and striking forms, and they have b ...

, a

marine Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (disambiguation) * Marine art * Marine biology * Marine current power * Marine debris * Marine energy * Marine habitats * Mari ...

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

mollusk Mollusca is a phylum of protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda. The ...

in the family

Aegiridae Aegiridae is a Taxonomy (biology), taxonomic family (biology), family of sea slugs, dorid nudibranchs, gastropod molluscs in the family (biology), superfamily Polyceroidea.Bouchet, P. (2015)Aegiridae Odhner, 1941.In: MolluscaBase (2015). Accessed ...

.Bouchet, P. (2015)
''Aegires albopunctatus'' MacFarland, 1905.
In: MolluscaBase (2015). Accessed through: World Register of Marine Species on 2016-05-21 Other common names include the salt-and-pepper nudibranch, small white nudibranch, white knight nudibranch, and white-spotted doris.

Distribution

The salt-and-pepper doris occurs in the Eastern

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is ...

, along the coast stretching from

British Columbia British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...

, Canada to

Baja California Baja California, officially the Free and Sovereign State of Baja California, is a state in Mexico. It is the northwesternmost of the 32 federal entities of Mexico. Before becoming a state in 1952, the area was known as the North Territory of B ...

, Mexico.Fahey S.J. & Gosliner T.M. 2004
A phylogenetic analysis of the Aegiridae Fischer, 1883 (Mollusca, Nudibranchia, Phanerobranchia) with descriptions of eight new species and a reassessment of Phanerobranch relationships.
Proceedings of the California Academy of Sciences, (4) 55(34): 613–689. It inhabits the low

intertidal zone The intertidal zone or foreshore is the area above water level at low tide and underwater at high tide; in other words, it is the part of the littoral zone within the tidal range. This area can include several types of habitats with various ...

and the shallow

subtidal zone The neritic zone (or sublittoral zone) is the relatively shallow part of the ocean above the drop-off of the continental shelf, approximately in depth. From the point of view of marine biology it forms a relatively stable and well-illuminated ...

, down to depths of 100 ft (30 m). The salt-and-pepper doris can be found in sheltered, rocky

tide pools A tide pool or rock pool is a shallow pool of seawater that forms on the rocky intertidal shore. These pools typically range from a few inches to a few feet deep and a few feet across. Many of these pools exist as separate bodies of water only ...

and on

wharf A wharf ( or wharfs), quay ( , also ), staith, or staithe is a structure on the shore of a harbour or on the bank of a river or canal where ships may dock to load and unload cargo or passengers. Such a structure includes one or more Berth (mo ...

pilings.

Description

The salt-and-pepper doris grows up to 0.9 in (23 mm) in length. Its body is somewhat shaped like a squarish

torpedo A modern torpedo is an underwater ranged weapon launched above or below the water surface, self-propelled towards a target, with an explosive warhead designed to detonate either on contact with or in proximity to the target. Historically, such ...

, and ranges in color from bright white to duller, yellowish-gray shades of white. As its common name references, the salt-and-pepper doris is noted for the small dark and white spots all around its body, which resemble ground table salt and black pepper. The larger, dark "pepper" spots appear black or dark brown in color, while the white "salt" flecks may not be very distinct on brighter white individuals; they are more apparent on grayer individuals. Some individuals may have very little "pepper" spots, or none at all. Like other members of its genus, the body wall of the salt-and-pepper doris is firm to the touch, as it is filled with

spicules Spicules are any of various small needle-like anatomical structures occurring in organisms Spicule may also refer to: *Spicule (sponge), small skeletal elements of sea sponges *Spicule (nematode), reproductive structures found in male nematodes ( ...

from the sponges it consumes. Its body is lined with irregular rows of short, cylindrical

tubercles 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, b ...

. Its

rhinophores A rhinophore is one of a pair of chemosensory club-shaped, rod-shaped or ear-like structures which are the most prominent part of the external head anatomy in sea slugs, marine gastropod opisthobranch mollusks such as the nudibranchs, sea hare ...

are yellowish in color and, like the tubercles along its body, are truncated and simple in shape. It has 3 gills or branchial plumes which are small, tripinnate, and each sheltered by a large, irregularly shaped tubercle. Near its mouth, the salt-and-pepper doris has small, lobe-like oral

tentacles In zoology, a tentacle is a flexible, mobile, and elongated organ present in some species of animals, most of them invertebrates. In animal anatomy, tentacles usually occur in one or more pairs. Anatomically, the tentacles of animals work main ...

. Its mouth is roofed by a thick, quadrangular mandibular plate and its

radula The radula (; : radulae or radulas) is an anatomical structure used by mollusks for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters ...

is broad and deeply grooved, with 16-22 rows of 17 teeth.

Ecology

Diet

The salt-and-pepper doris is specialized to feed exclusively on the

calcareous sponges The calcareous sponges or calcereans are sponges that make up the class Calcarea, characterized by spicules made of calcium carbonate in the form of high-magnesium calcite or aragonite. While the spicules in most species are triradiate (with three ...

of the genera

Leucetta ''Leucetta'' is a genus of sponges in the family Leucettidae, which was first described in 1872 by Ernst Haeckel. The type species is ''Leucetta primigenia'' Haeckel, 1872 by subsequent designation. In Australia, ''Leucetta'' species are found ...

Leucilla ''Leucilla'' is a genus of calcareous sponges in the family Amphoriscidae. Species: * '' Leucilla agitata'' Sim-Smith, Hickman & Kelly, 2021 * '' Leucilla amphora'' Haeckel, 1872 * '' Leucilla antillana'' Cóndor-Luján, Louzada, Hajdu & Klauta ...

, and possibly Leucosolenia.

Reproduction

Like all nudibranchs, the salt-and-pepper doris is a

simultaneous hermaphrodite Simultaneous hermaphroditism is one of the two types of hermaphroditism, the other type being sequential hermaphroditism. In this form of hermaphroditism an individual has sex organs of both sexes and can produce both gamete types even in the sa ...

. While mating, individuals wrestle for dominance, attempting to penetrate and impregnate the other with their

penis A penis (; : penises or penes) is a sex organ through which male and hermaphrodite animals expel semen during copulation (zoology), copulation, and through which male placental mammals and marsupials also Urination, urinate. The term ''pen ...

, which is lined with small, hooked spines.

References

Aegiridae Gastropods described in 1905 {{heterobranchia-stub