LARGE PECTINID BIVALVES THAT LIVE OFF THE WEST COAST OF NORTH AMERICA

Introductory Note 1: Bivalves belonging to family Pectinidae (the pectens) are commercially referred to as scallops.

Introductory Note 2: For some additional images, see my previous post (Nov. 27, 2017) concerning “Colors of Scallops”).

Introductory Note 3: Life position of a pectinid bivalve: 

Introductory Note 4: Morphologic parts of a right-valve exterior of a

pectinid valve:

    ____

Patinopecten caurinus (Gould, 1850)

This species, which is a free swimmer throughout its life, is the largest living scallop in the world. The average size of this bivalve in Alaska is 24 cm in diameter (Foster, 1991). Its valves, which are circular and nearly flat (with small auricles (“wing-like ears”) at the ends of the hinge, have 20 low ribs (Fitch, 1953).

The following information is primarily from <www.sealifebase.ca>

Common Names: “Giant Pacific Sea Scallop” and the “Weathervane Scallop.”

Exterior color: whitish brown; interior color: white.

Geographic Range: Eastern Pacific, from Pribilof Islands, Alaska; Washington; Oregon; and as far south as Point Sur, California (Ignell and Haynes, 2000).

Water Temperature: Temperate (preferred) to boreal. 

Depth Range/Habitat: Usually 60–120 m; total range 2–300 m; found in small depressions on sandy-gravelly substrates; free living (unattached).

Maximum Size: Diameter 22.8 cm (Coan et al. (2000, p. 240).

Other Characteristics: Shell is very lightweight and thin.

Fossil Record of the Species: Pliocene (CA) and Pleistocene (CA). 

 

(Top image): right-valve exterior and (bottom image) left-valve exterior of the same Recent specimen of Patinopecten caurinus from Skagway, Alaska. Height 16.5 cm, diameter 17 cm.

Right-valve exterior of a fossil specimen (middle Pleistocene age) of Patinopecten carurinus, Santa Barbara County, Southern California. Height 14.5 cm, diameter 16 cm.

Nodipecten subnodosus (G.B. Sowerby I, 1835)

Common Name: “Giant Lion’s Paw”

Exterior Color: Considerable color variation, from dull purplish-white to brilliant orange and to purplish orange. Interior color: separate bands of purple or white.

For pictures showing color variation, see pectensite.com/Nodipecten%20subnodosus.html 

Geographic Range: Pacific coast of Baja California Sur, Mexico [as far north as Guerrero Negro and Cedros Island] and into the Gulf of California [from as far north as Bahia de Los Angeles, Mexico and southward to the southern tip of Baja California] (Smith, 1991). In El Niño years, this species has been detected at Santa Catalina Island in southern California (Coan et al., 2000).

Water Temperature: Warm temperate to subtropical.

Habitat: Low tide to 110 m depth, in small depressions in sand. Absent near river deltas and estuaries.

Maximum Size: Length 21.7 cm (Coan et al., 2000, p. 242).

Other Characteristics: Shell is heavy and thick; 8 to 9 radial ribs, overlain by fine radial riblets; elongate nodes on the ribs are mainly on the main part (= the bulged-out) umbo region of the shell, when viewed from the side.

Fossil Record of the Species: Terrace deposits in Baja California, Mexico––Middle Pliocene and Pleistocene (Smith, 1991, p. 99).

(Top image) right-valve exterior and (bottom image) left-valve exterior of the same Recent specimen of Nodipecten subnodosus From the Gulf of California (exact location unknown), length 14.5 cm, diameter 15.4 cm, thickness (both valves together) 5.5 cm.

References:

Coan, E.V. and P. Valentich-Scott, and F.R. Bernard. 2000. Bivalve seashells of western North America (from Arctic Alaska to Baja California). Santa Barbara Museum of Natural History Monographs Number 2, Studies in Biodiversity Number 2, 784 pp.

Fitch, J.E. 1953. Common marine bivalves of California. Bish Bulletin no. 90, State of California Department of Fish and Game Marine Fisheries Branch, 106 pp.

Foster, N.R. 1991. Intertidal bivalves a guide to the common marine bivalves of Alaska. University of Alaska Press, 152 pp.

Ignell, S. and E. Haynes. 2000. Geographic patterns in growth of the giant Pacific sea scallop, Patinopecten caurinus. Fish. Bulletin 98:849–853. [free pdf available online].

pectensite.com/Nodipecten%20subnodosus.html 

Smith, J.T. 1991. Cenozoic giant pectinids from California and the Tertiary Caribbean Province: Lyropecten, “Macrochlamis,” Vertipecten, and Nodipecten species. United States Geological Survey Professional Paper 1391, 155 pp., 38 pls.

www.sealifebase.ca

“TURTLE BARNACLES”

Most people think of barnacles as being attached to one another [in colonies] or attached to boat bottoms, submerged bottles, sea shells, rocks, or even shoreline plants [see my recent post, June 2, 2023, on "Barnacles Living in Salton Sea of Southern California]. There are, however, some species of specialized barnacles that can attach to the carapaces of sea turtles and crabs, as well as to the skin of dugongs, and whales, etc. The generalized name “turtle barnacles” is commonly given to all these various specialized barnacles. 

This present post concerns a species of turtle barnacle found associated with a washed-up, dead sea turtle on a beach in the warm waters of the Gulf of California in Baja California, Mexico. An anonymous collector had identified the material as the barnacle Coronula testudinaria Linnaeus, 1758. Based on the available literature, I provide the updated taxonomy of this barnacle, which is be more accurately identified as Cheloniba testudinaria (Linnaeus, 1758). 

 Three views (top, bottom, and side) (length 31 mm, width 27 mm, and height 6 mm, respectively) of the shell of a sea-turtle barnacle “Chelonia testudinaria” from the carcass of a sea turtle found in the Gulf of California, Baja California. The total length and total width of the opercular plates (those in the center of the shell) are 11 mm and 3 mm, respectively. 

The classification of turtle barnacles is the following:

Phylum Arthropoda/Class Crustacea/Subclass Cirripedia/Order Thoraeica/Suborder Ballanomorpha/Superfamily Coronuloidea/Family Coronulidae.

Chelonibia is the largest and least specialized genus of turtle barnacles, and C. testudinaria is common in all warm seas, including the eastern Pacific (Morris et al., 1980). According to Zardus and Hadfield (2004), this barnacle is perhaps the most cosmopolitan of turtle barnacles, and is the largest in size (diameter up to 120 mm). It is occasionally found on the scales of the head and flippers of sea turtles. In total, it is known to associate with seven species of marine turtles.

The shell of this species characterized by its low, dome-shaped shell, supported internally by numerous closely spaced, radiating septal buttresses (Morris et al., 1980). The shell is strong, oval shaped, smooth, and white in color, and grooved with six prominent radii that create a “star-like” appearance (Darwin, 1854). The widest part of the shell is on the posterior of the shell. The four opercular plates (those that close off the operculum) are long and narrow. 

Chelonibia is the least specialized genus of turtle barnacles. Superficially, its wall appears to be made up of six plates, but studies show that early in its development, there are actually eight plates. In the initial shell development (within only 24 hours) however, the rostro-lateral plates undergo coalescence (fusion), thereby producing seemingly only six plates (Zardus and Hadfield, 2004). This apparent “tripartite” rostrum of Chelonibia is a vestiage of the eight-plated ancestry of all balanomorphs (Morris et al., 1980).

Based on fossil occurrences in the Mint Springs and Byram formations of Mississippi, genus Chelonibia has a geologic range from the Oligocene to recent (Zullo, 1982).

References Used: 

Darwin, C. 1854. A monograph on the sub-class Cirripedia with figures of all the species. The Balanidae, the Verrucidae, etc. London: Ray Society, 684 pp. Available online (free) at: darwin-onliine.org.uk

Morris, R.H., D.P. Abbott, and E.C. Haderlie. 1980. Intertidal invertebrates of California. Stanford University Press, Stanford, California, 690 pp.

Zardus, J.D. and M.G. Hadfield. 2004. Larval development and complemental males in Cheloniba testudinaria, a barnacle commensal with sea turtles. Journal of Crustacean Biology 24, issue 3, pp. 409-421. Available online (free) at: https://doi.org/10.1651/C-2476

Zullo, V. A. 1982. A new species of the turtle barnacle Chelonbia Leach, 1817, (Cirripedia, Thoracica) from the Oligocene Mint Spring and Byram Formations of Mississippi. Mississippi Geology 2, no. 3:1-6. Available online (free).

THE CHILEAN “ABALONE” SHELL

Concholepas concholepas (Bruguiére, 1789) is the intertidal gastropod whose shell strongly resembles that of a valve of a bivalve, and to a lesser degree, resembles an abalone gastropod. Concholepas concholepas, which is commonly referred to as the “barnacle rock” shell, belongs to family Muricidae and to subfamily Rapaninae (www.marinespecies.org). Like most muricids, Concholepas is a predatory gastropod. The shell of Concholepas, which can up to 8 cm in length, has a very reduced spire, thereby creating the appearance that this shell is of a large limpet (Anonymous, 1971) or of an abalone. In older literature, this gastropod went by the synonymous name of C. peruviana. 

Conchoplepas concholepas is endemic to Peru and Chile, where is common and lives in cold-waters of the rocky shoreline littoral zone in the Peruvian and Magellanic Provinces. This gastropod, referred to as “loco” (in Chilean Spanish), is edible and has long been used as a food source. Locally, the effects of over harvesting by humans can be significant and severe. This large soft “foot” is tasty and wild-harvested by divers and then packed in salt water. 

A growth series, left to right, of the exteriors of young to mature individuals of the gastropod C. concholepas. The largest specimen  is 9 cm length and 6.7 cm wide. The next image shows the interior views of these same shells, as well as the operculum (the brown organic material that covers the aperture of the shell) of the largest young shells shown.  This operculum is 3 cm high.

The fossil record of this genus is middle Miocene to Recent. Fossils of this genus are found only in Peru and Chile (DeVries, 1995). 

REFERENCE:

Anonymous. 1971. Shells of the West Coast of the Americaqs: Concholepas concholepas. The Tabulata, July, 1971, p. 17.

DeVries, T.J. 1995. Concholepas Lamarck, 1801 (Neogastropoda: Muricoidea): A Neogene genus native to South America. The Veliger 38(4):284-297. Pdf available free on biodiversity.org

www.marinespecies.org

JANTHINA JANTINA, THE VIOLET “FLOWER” OF THE SEA: A MOST UNUSUAL GASTROPOD

This post is about the unusual gastropod Janthina janthina (Linnaeus, 1758). Its scientific name is derived from new Latin, janthina [feminine of janthinus], meaning violet-blue, and from the Greek word anthos [meaning flower]. Its common name is “violet sea snail” or “purple-storm snail.” This last moniker is explained below.

Janthina janthina is a holoplanktonic [pelagic] sea snail. It spends its entire life cycle as a passive floater at or near the surface of tropical and warm-temperate oceans throughout the world. All Janthina are born being males, but, as they develop, they become females. Although their larvae (referred to as veligers) swim, the adults cannot swim. This gastropod produces rafts made of bubbles derived from their own mucus. These rafts are commonly mistaken as eggs. They can be common in Mexico and Peru. In some cases, large groups (“colonies”) of them float together, thus after storms, they are prone to being stranded along beaches; hence the derivation of the name “purple-storm snails.” Their shells can be as big as height 38 mm and width 40 mm. Janthina janthina feeds on pelagic (floating) microscopic hydrozoans, as well as on jelly fish and the jelly-fish looking Portugese-Man-of War. The shell of Janthina absorbs the purple-color ink of their prey.

Life position of Janthina janthina. Image after Younge and Thompson (1976, pl. 5).

The very fragile, paper-thin shell (lighter-than-air) of Janthina janthina floats upside-down (with its spire down) during life. This position is just the opposite of most other gastropods. The Janthina janthina shell is also reverse countershaded: with the spire whorls light colored, and the basal whorl dark colored. This countershading is similar to that found in fish because it provides protection from predators by being nearly invisible to them.

Basal view of a Janthina janthina shell (2.5 cm wide) from Florida. The basal (purple side) of the shell faces the sky during the adult life of this gastropod.

Top view of the same Janthina janthina shell as shown above. This white side of the shell faces the ocean bottom when the shell is floating in the ocean.  

Side view (2.3 cm height) of the same Janthina janthina shell as shown above.

References Cited:

Linnaeus, C. 1758. Systema Naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Edition decima, reformata (10^th revised edition), vol. 1, 824 pp. Laurentius Salvius: Holmiae. Total pages 772

 Available online free at https://biodiversitylibrary.org/page/726886

Yonge, C.M. and T.E. Thompson, 1976. Living marine mollusks. William Collins Sons & Co., London, 288 pp.

FLAMINGOS, INCLUDING FOSSIL ONES IN CALIFORNIA

Flamingo birds are very distinctive among living birds because of their pink or pinkish coloration and very long legs. They are social animals that live in large colonies, and they can be highly vocal. A group of flamingos (also spelled flamingoes) is called a flamboyance (en.wikipedia).

Two flamingos at Los Angeles County Zoo (photo by the author). 

BIOLOGY 

Flamingo legs actually bend just like human legs, but a flamingo’s knee is really its ankle. When a flamingo leg bends, it is its ankle that you seen hinging (en.wikipedia).

The reason flamingos are pink is that they obtain the pigment from the food they eat, which consists of microscopic algae and brine shrimp (the latter of which also eat the  microscopic algae). The flamingos, which are technically speaking, filter feeders, readily metabolize the pink pigment in their food and transfer it to their feathers. There is a range in the pink coloration of flamingos, from pink, to pinkish white, to whitish pink. Determination of which species of flamingo is which is usually that not easy to discern, just based just on coloration.

A flamengo eats with its head upside down in the water, with the bill pointed at its feet. It then sweeps its head from side-to-side, using its tongue to pump water in-and-out of its bill. Comb-like plates along the edge of the bill create a filter for water to rush out, while trapping the food inside (en.wikipedia).

Flamingo parents (both of them) feed their chicks crop milk (regurgitated from the adult's crop, an internal organ). 

HABITATS

Some species of flamingos are found typically in shallow freshwater lakes or in salty or brackish waters (e.g., alkaline or “soda” lakes, like the ones mentioned in my previous post concerning lepidolite in Chile). The tough leg skin of flamingos can tolerate these toxic waters. Flamingos can live also in mangrove swamps, tidal flats, and sandy islands in the intertidal zone (seaworld.org).

Flamingos are generally non-migratory birds, cut they can move around locally to adjust to climate change and waters levels in their breeding areas. They can fly long distances; approximately 370 miles in a single night at about 35 mph. They often fly at night so as to avoid predation by eagles (seaworld.org). 

CLASSIFICATION

Flamengos represent a type of wading bird but are not waterfowl. Although flamingos have long legs for wading, they are genetically most similar to the squat, short-legged grebe birds, which are diving birds (see Tuinenf et al., 2001). According to en.wikipedia, their classification is:

Class Aves

Order Phoenicopteriformes

Family Phoenicopteridae

Genera: 8 known genera; 5 are extinct, 3 are extant [at least one DNA study, however, indicates   only two genera---see Frias-Soler et al. (2022)].

Extant (living) Species: 6

Phoenicopterus roseus—parts of Africa, southern Europe, southwest Asia. This is the most widespread flamingo and also the largest flamingo in size.

Phoenicopterus chilensis––temperate southern South America.

Phoenicopterus ruber––Caribbean islands, Caribbean Mexico, southern Florida, Belize, coastal Columbia, northern Brazil, Venezuela, and the Galápagos Islands (which is an isolated population (about 500 individuals with, therefore, low genetic diversity; also they are

smaller in size than other flamingos—see Frias et al., 2014). This species, which is commonly called the “American flamingo,” is the second largest flamingo in size. This species is closely related to P. roseus and P. chilensis, according to Luo et al. (2016).

Phoenicoparrus andinus–––High Andes in Peru, Chile, Bolivia, and Argentina.

Phooenicoparrus jamesi–––High Andes in Peru, Chile, Bolivia, and Argentina.

Phoenicoaias minor–––Africa (Great Rift Valley) to northwest                India. Individuals are the most numerous and also the  largest in size of all flamingos.

The classification of flamingos is in a state of flux because of recent DNA studies.

GEOLOGIC AGE RANGE

The known geologic age range of flamingos is middle Oligocene (in central Europe) to modern day. The massively built Phoeniconotius pyrensis of late Oligocene age is known from southern Australia. It is important to emphasize that bird fossils are all very rare. Also, bird bones are fragile because they are hollow with thin walls. Therefore, bird fossils do not preserve very well.

CALIFORNIA FOSSIL OCCURRENCES

Flamingo remains have been recovered from late Pliocene in the Mojave Desert region in southern California. Their presence suggests shallow-lake environments with a rich microscopic food source (Jefferson, 2006:p. 149 and also fig. 9.8).

Leg bones of a rather small flamingo species of late Pleistocene age have also been recovered from Lake Manix, California. Nearly complete leg bones of Phoenicopterus minutus Howard, 1955 were found (an example is figured below), as well as a fragment of another species of this genus. 

Example of a nearly complete (length 22.2 cm) tibiotarsus (= long bone of the lower leg) of Phoenicopterus minutus Howard, of late Pleistocene age, from Lake Manix, California (from Howard's pl. 50, fig. 4).

References Cited

en.wikipedia

Frias-Soler, R.C. and eight others. 2022. Phylogeny of the order Phoenicopteriformes and population genetics of the Caribeean flamingo (Phoenicopterus ruber: Aves). Zoological Journal of the Linnean Society, v. 196, issue 4, pp. 1485-1504. 

[pdf low cost].

Howard, H. 1955. Fossil birds from Manix Lake, California. Descriptions of late Pleistocene bird remains, including a new species of flamingo. United States Geological Survey Professional Paper 264:199–205. [pdf available free).

Jefferson, G.T. 2006. The fossil birds of Anza-Borrego. In Fossil Treasures of the Anza-Borrego Desert. California State Parks, pp. 151-160.

Luo, X., X. Kang, and D.Z. Zhang. 2016. Complete mitochondrial genome of the American flamingo, Phoenicopterus ruber (Phoenicopteriformes, Phoenicopteridae. DNA Mapping, Sequencing, and Analysis, v. 27, issue. 5. [pdf expensive].

seaworld.org 

Simthsonian magazine @ nationalzoo.sci.edu, or national.si.edu

Tuinenf, M.V. and three others. 2001. Convergence and divergence in the evolution of aquatic birds. Proceedings of the Royal Society B, Biological Sciences, v. 268, issue 1474. [pdf moderate cost].