No Bones

A strange squid appears even stranger IRL

For readers over 30 years old, IRL means "in real life".

Combfin squids in the family Chtenopterygidae are small, muscular, midwater squids that occupy tropical to subtropical waters probably at depths of 500-1000m during the day and near-surface waters at night. The posterior end of the mantle is broadly rounded. The fins are peculiar: they consist of muscular pillars called fin ribs, connected by thin membranes. The membranes are often torn in captured specimens, giving the fin the appearance of a comb; hence the family name. The fin extends nearly the full length of the mantle.

Every time I have caught Chtenopteryx they have been pretty beaten up. A few years ago, when E/V (Exploration Vessel) Nautilus was conducting ROV operations on Thessaloniki Mud Volcano in the Mediterranean, they recorded video of "a small squid" swimming near the ocean floor at about 1300 m. I finally got to see it recently and it was, as far as I know, the first in-situ observation of Chtenopteryx, probably C. sicula. As you can see from the frame grabs on the Tree of Life and the Nautilus Live video below, this strange squid looks even weirder when it is alive. 

When first encountered, chromatophores (tiny pigment sacs) were expanded over the fin ribs, emphasizing these unusual structures. On the dorsal mantle above the digestive gland was a dark oval patch. Also, patterns of chromatophores on the lateral arms are displayed and then fade. The display of these patterns was surprising to cephalopod biologists and the purpose of the displays is unknown. Seeing it near bottom may seem unusual for a midwater squid, but it may just be at the deepest part of its daily vertical migration.

by Mike Vecchione

“GALLERY OF CARCINOLOGISTS” Returns to IZ-NMNH

The Department of Invertebrate Zoology (IZ) holds a unique collection of more than 400 portraits of influential scientists that have worked on crustaceans (carcinologists) from Aristotle to the present. Accompanying the portraits are biographical files that contain valuable information on their life and works. This collection has been painstakingly gathered by various IZ curators, with help of outside colleagues, over many decades, and holds valuable information for biologists and historians of science. The portraits consist of large format photographs and negatives, as well as line drawings (some original), and many were framed and exhibited on the hall walls of IZ, each with a brief biographical summary. This collection exhibited on the halls of IZ floors on the West Wing of the Natural History building was originally called the “Rogue Gallery”.

The biographical files are stored in acid-free reprint boxes and contain original obituaries or copies of biographies, photographs and slides, and in some cases, news clippings and/or unpublished notes on life aspects of the scientists. Given the size and importance of this collection, all components were scanned and digitized over the last decade with the help of several hard working student interns. In a digitized format, this unique resource is accessible to researchers and interested users around the world, and eventually will be posted online.

With downsizing and renovation of the Natural History building (NHB), the “Gallery” exhibit was removed from the walls and moved to for temporary storage at the Museum Support Center (MSC, Suitland, MD).  The portraits were wrapped and packed into storage bins to await their next showing.  Fast forward 4 years (and 2 moves), the “Gallery” once again is up and gracing the walls of the Department of Invertebrate Zoology at NHB. Drs. Rafael Lemaitre and Stephen Cairns were instrumental in making this happen.  Dr. Cairns assisted with selection and placement of the portraits.

A small selection of portraits and corresponding biographies is presented here.

Just a few of the storage bins packed with framed portraits and ready for delivery to NHB.

Selecting and moving Gallery portraits from MSC to NHB. Dr. Cairns holds a portrait of Dr. Paul Illg destined to be hung outside Dr. Jon Norenburg’s office at NHB, by request.

Paul Louis Illg (23 September 1914 – 10 May 1998)

Professor of Zoology, University of Washington. Had an illustrious career in life sciences, and contributed to making his University’s Seattle campus and Friday Harbor Laboratories, one of the leading institutions in the world for studying marine zoology, especially invertebrates. Published prodigiously for more than 50 years on parasitic copepods, particularly those living in ascidians. His research on microscopic ascidicolous copepods greatly extended biological and taxonomic knowledge, and illuminated evolutionary processes in these extremely complex parasitic crustaceans. His work is without equal in the systematics literature.

Arranging the portraits after they arrived back to the halls of IZ at NHB.

First ones first….Dr. Ted Bayer’s portrait was hung outside Dr. Stephen Cairns’ office. (Dr. Cairns was a student of Dr. Bayer.)

 

Frederick “Ted” Merkle Bayer (31 October 1921 – 2 October 2007)

Received his BS from the University of Miami, and MS (1954) and PhD (1958) from George Washington University. Published over 130 papers and books on the taxonomy and natural history of soft corals, describing over 170 new species, 40 genera, and three new families. Species from different groups of animals have been named in his honor, including the hydroid Hydractinia bayeri, described by the Emperor of Japan, Hirohito. A curator at the Smithsonian Institution (1975 until retirement in 1996); emeritus researcher until 2006.

Not a carcinologist, but an outstanding bio-illustrator, he was tasked to create detailed water color sketches of color patterns of live Trapezia, coral reef crabs.  These sketches and associated field notes are now part of the Illustration Archives of the Department of Invertebrate Zoology, and have become extremely useful for modern revisionary taxonomic studies of these spectacular and ecologically important reef crabs.

 

CLASSIC CARCINOLOGISTS:

Georges Cuvier (23 August 1769 – 13 May 1832)   

French anatomist considered the founder of the sciences of comparative anatomy and paleontology. Worked at the Museum of Natural History, Paris. Was Chancellor of the University of Paris, and served in the cabinet of Louis XVIII. An antievolutionist, he became the most eminent European scientist of his time, and virtually an intellectual dictator in the field of biology. Perfected the animal classification system of Linnaeus by grouping related classes into broader groups he called phyla: Vertebrata, Mollusca, Articulata (jointed animals), and Radiata (everything else). In doing so he stressed internal structures as indicative of relationships, rather than external features. Made important collections of crustaceans and published on groups such as the isopods.

Charles Robert Darwin (12 February 1809 – 19 April 1882)

His participation as naturalist in the 5-year voyage of exploration of the H.M.S. “Beagle” (1831-1836) made this expedition the most important in the history of biology. His observations led him to propose in 1858 (jointly with A.R. Wallace) the famous theory of evolution, detailed in “The Origin of Species” (1859). Began work on barnacles in 1846, and intensively studied their larval development, metamorphosis and adult morphology. His 4-volume work on living and fossil barnacles (1851,1852,1854,1855) elucidated their affinities, functional morphology, and evolution, establishing a classification still used today. A painstaking perfectionist in collecting and classifying his information, he was a man of independent means. Member of The Geological Society of London.

Henri Milne Edwards            (23 October 1800 - 29 July 1885)   

Head chair of Crustacea, Arachnida and Insecta, and also of Mammals and Birds, Muséum national d’Histoire naturelle, Paris. Great French morphologist and classifier. Best known for his multi-volume work considered the first breviary of carcinologists: “Histoire naturelle des Crustacés” (1834-1840), where he named 1400 species and 350 genera. First to propose idea that the crustacean body is arranged in series of homologous segments each with a pair of appendages.

Alphonse Milne-Edwards (13 October 1836 - 21 April 1900)        

French carcinologist, succeeded his father (H. Milne Edwards) as chair of Mammals and Birds, and became director of the Muséum national d’Histoire naturelle, Paris. Studied fossil crustaceans, and published many works documenting the diversity and morphology of decapods, mostly Brachyura and Anomura, from classic exploratory expeditions conducted on ships such as the "Travailleur", "Talisman", and the "Blake".

James Dwight Dana (12 February 1813 – 14 April 1895)    

Professor, Yale College. One of the first professional American scientists. Attained the rank of zoologist, then leaving this for geology, his chief field. Became known in 1836 with a treatise on mineralogy, followed by a series of short papers on copepods. Geologist and Zoologist of the “U.S. Exploring Expedition” (1838-1842), one of the great events in the history of science in the United States. In his monumental work “Report on the Crustacea” (1853-1855), described hundreds of new species, and presented a philosophical treatment of the classification, relationships, and distributions of species. Editor for 50 years of “The American Journal of Science”, and founder of the National Academy of Science.

Classic carcinologists: Georges Cuvier, Charles Darwin, Henri Milne Edwards, Alphonse Milne-Edwards, James Dwight Dana.

Modern day carcinologists at the National Museum of Natural History: Austin Beatty Williams, Thomas Elliot Bowman, Isabel C. Pérez Farfante, and Fenner Albert Chace, Jr.

 

SMITHSONIAN INSTITUTION/NMFS STAFF

Austin Beatty Williams (17 October 1919 - 27 October 1999)

Research Scientist, Systematics Laboratory, National Marine Fisheries Service, based at the National Museum of Natural History, Smithsonian Institution. Obtained his Ph.D (1951) at the University of Kansas, studying Ozark crayfishes. His numerous publications covered the taxonomy, systematics, biogeography, and evolution of various decapod groups, both Fossil and Recent. Best known for his invaluable and widely used "Marine decapod crustaceans of the Carolinas" (1965), and its later expanded version "Shrimps, lobsters, and crabs of the Atlantic coast of the eastern United States" (1984). He was co-founder and president (1983-1985) of the Estuarine Research Federation, and was an active member of The Crustacean Society, and the Biological Society of Washington, among others.

(Photo: 1997, taken during ceremony in his honor)

Thomas Elliot Bowman III (21 October 1918 – 10 August 1995)

Curator, Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institution. Produced 163 papers on isopods, copepods, amphipods, mysids, and mictaceans. His mastery of crustacean comparative anatomy and morphology led him to produce classic, provocative studies such as on structural homology of the telson and on the evolution of stalked eyes.

Isabel C. Pérez Farfante (24 June 1916 – 20 AUGUST 2009)

Carcinologist Emeritus, U.S. National Marine Fisheries Service, Systematics Laboratory. Born in La Havana, Cuba, she received her Ph.D. from Radcliffe College (1948). She was professor and researcher at the University of Havana; director of the Cuban Centro de Investigaciones Pesqueras; and associate in Invertebrate Zoology, Museum of Comparative Zoology, Harvard University. She has authored zoology textbooks, and numerous papers on the systematics of penaeoid shrimps, most notably landmark studies of the commercial genus Penaeus. She is senior author of the book “Penaeoid and sergestoid shrimps and prawns of the world” (1997). (Married name: Isabel C. Canet)

Fenner Albert Chace, Jr. (5 October 1908 – 30 May 2004)

Zoologist Emeritus, National Museum of Natural History, Smithsonian Institution. Born in Fall River, Massachusetts. Obtained his Ph.D. in 1934 from Harvard University. He was Assistant Curator of Invertebrates (1934-1942) and Curator of Crustacea (1942-1046), at the Museum of Comparative Zoology, Harvard University. Joined the staff of the U.S. National Museum* in 1946 where he worked until his retirement in 1978. He then completed his 7-part study of the caridean shrimps from the “Albatross” Philippines expeditions (1907-1910), published in Smithsonian Contributions to Zoology between 1983 and 1997. His interests centered primarily on caridean shrimps, and he is considered by his peers as one of the most influential and respected specialists on caridean shrimps in the latter half of the 20^th century.

Mary Jane Rathbun (11 June 1860 – 14 April 1943)

Ascended from “copyist” to assistant curator in charge of the Department of Marine Invertebrates, U.S. National Museum. Prodigiously productive, considerably advanced knowledge of fossil and Recent decapod crustaceans of the world, describing 1147 new species, 63 genera, and 5 higher categories. Best known for her unparalleled, monumental 4-volume monograph of New World brachyuran crabs, and a treatise on freshwater crabs.

Waldo LaSalle Schmitt (25 June 1887 - 5 August 1977)

Head curator, Department of Zoology, U.S. National Museum. Succeeded M.J. Rathbun. His tireless collecting efforts during numerous expeditions worldwide led to the immense holdings of the national collections. His dedication to the advancement of invertebrate systematic zoology contributed to the unmatched growth and international recognition of the Department. Author of numerous taxonomic studies on decapods and stomatopods, and the popular book "Crustaceans" (1^st printed 1931).

Raymond Brendan Manning           (11 October 1934 – 18 January 2000)

Senior Zoologist, Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, D.C.  Earned his BS (1956), MS (1959), and PhD (1963) from the University of Miami.  He published 278 papers on stomatopods and decapods, including landmark monographs and other studies on West African crabs, Indo-pacific dorippids, commercial geryonids, cave shrimps, and callianassids.  Above all, he was a master in stomatopods, and increased the known species from a handful to nearly 500 worldwide.  In all, he named 279 species, 138 genera, 5 subfamilies, 19 families, and 3 superfamilies of extant decapods and stomatopods, and at least 15 genera and 27 species of fossil decapods.  A tireless collector, he obtained more than 50,000 decapod and stomatopods for the Museum and other institutions.  One of the founders, and first President (1981-1983) of The Crustacean Society, from which he received in 1999 the “Excellence in Research Award”.

 

OTHER NOTABLE CARCINOLOGISTS:

Aristotle (384 – 322 B.C.)

Greek philosopher, founder of zoology and natural history. Organisms we now call crustaceans (decapods, stomatopods, copepods) can be identified in his “Historia Animalium” under the account of “bloodless” animals. His description of 180 different Aegean Sea animals is the precursor of all subsequent publications in marine biology.

Maria Sibylla Merian (12 April 1647 – 13 January 1717)

Artist-naturalist, born in the imperial city of Frankfurt am Main. She was not only skilled in watercolor and oils, but also was a keen observer of habits of caterpillars, flies, spiders, and other creatures. Her most famous works are her “Raupen”, and after traveling to America, her “Metamorphosis of the Insects of Suriname”, and “European Insects”, which include exquisite plates depicting life stages of insects.  She can be hailed as the first woman carcinologist as she prepared 60 crustacean paintings for Georg Everard Rumpf’s (Rumphius) 1705 book on the crustaceans from Amboina.

Jean-Baptiste P.A. de Monet de Lamarck (1 August 1744 – 28 December 1829)

French naturalist. Took a long time finding himself. As a soldier he fought with distinction in the Seven Years’ War. In 1781 he was appointed botanist to the king, and in 1793 (at nearly 50 years of age) professor of zoology at the Museum of Natural History in Paris, at which time he came into his own. Between 1815 and 1822 he produced the gigantic 7-volume work “Histoire naturelle des animaux sans vertèbres” which founded modern zoology. He coined the terms “vertebrate”, “invertebrate”, and “biology”. In his book “Philosophie Zoologique” he was the first biologist of rank to rationalize the evolutionary development of life. Unappreciated and often maligned in his time, he died blind and penniless.

Constantine Samuel Rafinesque (22 October 1783 – 18 September 1840)    

Born in Constantinople, Turkey, into a French-German family. He privately studied natural sciences, medicine and mapmaking. He was an eccentric, perhaps unbalanced man, but his intellectual breadth was enormous. A keen naturalist, nearly every one of his 900+ publications is rare, appearing in obscure places or journals. His carcinological work focused on the faunas of Sicily and the eastern U.S. Most of the numerous crustacean names he proposed never attained taxonomic status because of faulty descriptions, lack of illustrations, and his practice of not keeping specimens. His work was unfairly ignored or minimized by contemporaries. He died in poverty and isolation in Philadelphia, and his collections and books sold as junk. In early years he used the name Rafinesque-Schmaltz.

by Rose Gulledge

 

Visiting PhD Student Investigating Parasites of Mammals

I am a little hesitant to tell people outside of my research field what I study, which is surprising if you know me - I love talking about my research. It’s fascinating (and I’m not at all biased). I would like to think my enthusiasm for my research project is contagious; however, my fervor is often met with varying degrees of disgust. Why?

Because I study parasites. And not just any parasites; I study the roundworms, tapeworms, and flukes of rats and mice. Not only is there a stigma against parasites, but also against the rodents I collect. I will spare you the explanation of why rodents are awesome and mostly misunderstood, but I will be delving a bit more into the study of parasites.

These groups of parasites, the roundworms, tapeworms, and flukes, are collectively known as helminths. In most cases, these helminths reside in the body cavity, organs, and various tissues of their hosts. While their creepy crawly nature may repulse some people, they are remarkably important to individual hosts, populations, communities, and to the ecosystem as a whole, yet they are often ignored in many fields of study in the biological sciences. There is a growing body of literature attesting to their importance even outside of human and veterinary medicine (see citations below for a few examples).

Whitney working at the microscope picking worms.

 

Before scientists can determine the role of parasites in host evolution, community ecology, trophic ecology, and so on, we must first know more about parasite diversity and abundance. Parasites are largely understudied, and species new to science are still being discovered and described. Parasitological surveys of hosts have merit for documenting the diversity and abundance of parasitic species in hosts.

I approached Dr. Anna Phillips at the American Society of Parasitologists’ annual meeting in July 2015 about joining one of her research projects. Anna, a research zoologist and one of the curators of the invertebrate collections, is collaborating with researchers in Spain to investigate the parasite fauna of rodents and tree shrews from Borneo. Few studies have examined the parasites of these species from these localities, so this investigation is important to determine the diversity and abundance of the parasites of these hosts.

We have a few goals for this research. First, we will document the helminth diversity and abundance in these hosts. Second, we will describe species new to science. This will allow for these helminth species to be included in future ecological and evolutionary studies and considered in conservation management plans. Third, these helminths will be DNA barcoded – certain genes will be sequenced and input into an open access database for future use by other scientists (for example, for identification or phylogenetic studies).

This past May, I spent three weeks going through some of the rodent specimens looking for parasites. Unfortunately, I was only able to get through a small portion of the rodent samples – fortunately, this was due to the high numbers of parasites found in each specimen. Morphological and molecular identification for these first samples is ongoing; we hope to have the rest of the parasites collected and identified by next year. After identification, the parasite specimens will be deposited into the National Parasite Collection for future scientific use.

With such a large number of helminths found in the intestines of each rodent, you may wonder if the rodents and tree shrews were alive when they were collected. Yes, they were alive! So were they sick?

That is a more interesting question. Parasites can affect their hosts in a variety of ways – they can influence host reproduction, behavior, health, and life span. The effects and their magnitude differ between parasite species and host species, and are influenced by the number of parasite species and the number of individual parasites infecting the host.

Back to the original question – what about the rodents and tree shrews? I did not collect these specific rodents and tree shrews so I don’t know if they were lethargic, skinny, weak, acting strangely, in breeding condition, etc. We do have some clues about the parasites’ effects on their host’s health though. I examined the organs where the parasites were located, and in most cases, I only found slight physical damage, often to the intestinal villi. There were some specimens with more serious damage: intussusceptions, where a portion of the intestine inverts itself, and multiple perforations of the intestinal and stomach wall were present.

Intussusceptions in humans and other animals can cause abdominal pain, vomiting, and diarrhea. While this condition has been linked to infection with parasites, there are other causes too. There is no way for us to definitively say that these intussusceptions were results of parasitic infection. If they were linked, we would be able to conclude that these parasites are having a negative impact on their hosts’ health.

We can conclude that the perforations of the organ walls were caused by the parasites. I found a number of nematodes half buried in the walls of the stomach and the large intestine. I did not find any of the worms passing completely through the organ wall; rather, the walls were thickened where the parasites had burrowed in. The hosts likely suffered abdominal pain when the worms originally burrowed into the organ walls, and may have also experienced blood in the feces or diarrhea.

Roundworms embedded in the wall of a mammal’s stomach.

With parasitological studies such as this one, we are limited to making observations and finding correlations between a parasite’s presence and possible effects on the host. Experimental and manipulative studies are required to definitively link cause and effect, but observational studies are still very important for determining the biodiversity and abundance of parasites, as well as driving the formation of hypotheses linking parasites and their effects on the host.

In the next few months, we will continue to sort through the rodent and tree shrew specimens, collecting, sorting, and counting the helminths found. Helminth specimens will be sequenced for DNA barcoding, prepared for museum installation, and described as a new species if they are species new to science. We look forward to the exciting discoveries and results from this work!

By Whitney Preisser, a fourth year doctoral student in the Department of Wildlife and Fisheries Sciences at Texas A&M University. Her research investigates the latitudinal diversity gradient of parasitic helminths in North America. She can be reached at wpreisse *at* tamu.edu.

Further Reading

1. Altizer, S, CL Nunn, and P Lindenfors. 2007. Do threatened hosts have fewer parasites? A comparative study in primates. Journal of Animal Ecology. 76:304-314.
2. Fenton, A and MA Brockhurst. 2008. The role of specialist parasites in structuring host communities. Ecology Research. 23:795-804.
3. Palm, HW, S Kleinertz, and S Rückert. 2011. Parasite diversity as an indicator of environmental change? An example from tropical grouper (Epinephelus fuscoguttatus) mariculture in Indonesia. Parasitology. 138:1793-1803.
4. Ricklefs, RE. 2015. Intrinsic dynamics of the regional community. Ecology Letters. 18:497-503.
5. Wood, CL, JE Byers, KL Cottingham, I Altman, MJ Donahue, and AMH Blakeslee. 2007. Parasites alter community structure. Proceedings of the National Academy of Sciences of the United States of America. 104:9335-9339.
6. Dougherty, ER, CJ Carlson, VM Bueno, KR Burgio, CA Cizauskas, DP Seidel, NC Harris. 2016. Paradigms for parasite conservation. Conservation Biology. 4:724-733.

A blast from the past -- linkage between IZ and WWII history

In June 2016 we received a request from William Langford of Plattsmouth, Nebraska for a photograph of shells that were donated to the museum by his grandfather (Daniel Boone Langford) during the first half of the 20^th century. William recalled visiting IZ and seeing some of these specimens 44 years ago. His grandfather was a shell collector whose knowledge of the Pacific Island reefs and beaches (acquired in part through his fieldwork) was so extensive that the United States Navy employed him as a civilian expert to assist with the planning of the amphibious invasion of Okinawa during WWII (see W.J. Holmes, Double Edge Secrets, U.S. Naval Intelligence Operations in the Pacific During WWII, Naval Institute Press, 2012). 

Daniel Langford, who passed away in 1954, discovered a number of new mollusk species, several of which were named after him by Smithsonian curators (including William Healy Dall) and other malacologists.  We assembled a plate with images of some of these species and sent photographic copies to William Langford and his two sons.  Many thanks to volunteer Nick Raymond, and Yolanda Villacampa for taking the photographs of these specimens.

Selection of shells collected by Daniel Boone Langford.

 

For those who are interested, some of the details of Daniel Langford’s life can be found in Harald Rehder’s memorial sketch of Langford’s friend and brother in law Ditlev Thaanum, who was also a well-known Pacific shell collector.

By Bob Hershler

Anemone Recently Spotted by NOAA's Okeanos Explorer Potentially Packs a Wallop

A couple of days ago, the Echinoblog (by IZ's Chris Mah) posted this wonderful picture of a withdrawn sea anemone in the family Aliciidae from a recent Okeanos Explorer Dive observed on Ahyi Seamount in the Mariana Islands region at 275 meters.

A seldom seen sea anemone in the family Aliciidae, with its lengthy tentacles withdrawn. Captured on film by NOAA's Okeanos Explorer.

Dr. Dave Pawson, Curator Emeritus has apparently encountered these sea anemones before!  Upon reading Chris' Echinoblog post on the recent Okeanos observations, he shared a “real world” encounter with an aliciid anemone in the Atlantic.

"We picked up one of those in the Bahamas years ago…a small animal that was about 6 inches long when we laid it out in a dish on the mother ship, but when in situ, the tentacles extended out about 1.5 meters!  We were looking at this weird animal in the dish, and wondered what the scattered knobby structures were on the body.  Could they be “buds” – was the animal reproducing asexually?  I touched one of the knobs with a fingertip, and received a jolt that felt like a million volts of electricity!  The knobs were masses of nematocysts (stinging cells).  My fingertip was very painful for some hours, but it survived; in in fact I’m typing this e-mail with it, in my usual two-fingered manner."

Below is a fantastic picture by Philippe Guillaume of a similar-looking aliciid anemone with tentacles extended. Explore his Flickr page for additional images.

 By Chris Mah

The Strange Scanning Eyes of a Swimming Sea Snail

We know about many bizarre visual characteristics of animals living in the dim light of the deep sea. One of the strangest such adaptations is the scanning eye of an atlantid heteropod mollusc. Heteropods are snails that spend their entire lives swimming in the open ocean. [Heteropods are sometimes called Sea Elephants, and are also known as pterotracheoids.] Their eyes have a well-formed spherical lens with the retina the correct distance away for the lens to focus an image. The strangeness is in the shape of the retina and how it is used. In atlantids, the earliest diverging family group of heteropods, the retina is a narrow band. To view its environment, the animal rotates the narrow retina up and down periodically through a 90 degree arc. We think that when it does this, the animal scans successive slices of the environment and then mentally assembles a complete image much like we do when we watch a television screen; a TV picture is also comprised of many separate lines displayed successively but so rapidly that we see them as a complete picture.

  

Having a full-sized retina is a problem for animals of the ocean's "twilight zone" where predators look upward for silhouettes of potential prey against the dim light filtering down from the surface. A large retina makes a large silhouette/target because, in order to function, the retina has to absorb as much light as possible. A narrow scanning retina would reduce this problem while still functioning to monitor the visual environment effectively.

I knew about heteropod eyes, and teach about them in Deep-Sea Biology. However, I had never watched one in action until I went to sea this month as part of a group studying the swimming animals of the deep Gulf of Mexico. We caught this Oxygyrus inflatus and I was able to record the video by shooting with my cell phone through the eyepiece of a microscope in the cramped laboratory of a rolling research ship.

By Mike Vecchione

The Amazing Hydroid Diversity in the Deep Sea

I’m Marina Fernandez, a PhD candidate from the University of São Paulo, in Brazil. Since February, I’ve been studying benthic hydroids from the NMNH-SI collection, under supervision of Dr. Allen Collins.

Hydroids are incredibly beautiful and diverse sea animals from the phylum Cnidaria. Their morphological and biological traits can vary greatly from one species to another. An evident variation is in size, with individuals ranging from a few millimeters to more than a meter. Also, most species grow in colonies, but some are solitary. Among colonial forms, the polyps composing one same colony can have different morphologies and functions – some are specialized in feeding, others in reproduction, and there can be a third group responsible for defending the colony. Even more striking is the fact that some hydroid species release a medusa, a life cycle stage in which these animals live in the plankton, where they release gametes for reproduction. Some species do not release a medusa, however, and thus it is the benthic stage that produces gametes.

Euphysa aurata Forbes, 1848, a solitary benthic hydroid from 799 meters depth in the North Atlantic Ocean. This hydroid has a swimming adult medusa stage in its life cycle.

Such kinds of diversity within a group make us wonder if different forms are evenly distributed among different environments of the sea. Studying how traits correlate with environments may help us understand how they evolved. And that’s what I’m trying to do here: associate information on traits from specimens in the collections with the place where they occur, in order to understand patterns of distribution. Some of the traits I’m looking are size, colony ramification patterns and presence of certain structures. This is then combined with information from the literature regarding the life cycle, that is, if a medusa is released or not.

Halecium dubium Fraser, 1941, a colonial hydroid, collected at 3,235 meters depth in the North Atlantic Ocean. This species does not release a swimming medusa stage as part of its life cycle.

This search for patterns is focused mainly on bathymetric gradients. As you go deeper in the ocean, the sunlight decreases rapidly until complete darkness. Without light, and hence photosynthesis, the phytoplankton, which is the primary food source in the ocean, can no longer survive. At those depths, food must somehow arrive from surface waters (except in chemosynthetic environments such as hydrothermal vents), making food scarcer as you go deeper. Temperature also decreases quickly, until it stabilizes below 1000 meters. Hard substrates are more difficult to find on deeper parts of the sea, the ocean floor being mostly formed by muddy bottoms in the abyssal plains. All these variations make the deep sea a very interesting environment for studying the diversity of traits in hydroids.

By Marina Fernandez, Visiting Grad Fellow

Sea Slug Senses

Chromodoris kuniei from Papua New Guinea

Nudibranchs are colorful marine slugs that are found in almost all shallow water areas around the world. Sadly, they cannot enjoy the beautiful colors and patterns that they have, because their eyes do not allow them to see in the same way humans (and many other animals) do. This leads to a few questions. Since they can't see the color patterns, what exactly can their eyes do? What do these slugs use their eyes for? And finally, are there other ways they can sense their environment? They have to get around somehow, right?

 

Hexabranchus sanguineus from Papua New Guinea

Nudibranch eyes are located on the head, just at the base of structures called rhinophores (we'll look at these in more detail in a bit). They are extremely small, and as such are difficult to see in photographs (you can see a couple on this Sea Slug Forum page: www.seaslugforum.net/find/2377). From research that has been done in the past on eyes in nudibranchs, we know that the eyes are primarily used in a very simple way, to detect dark and light. Once they sense a change in the light intensity, nudibranchs exhibit a behavior called phototaxis, referring to the movement of an organism toward or away from a light stimulus. Whether they move toward or away depends on the species, since some are active during the day (move toward the light) and others at night (move away from the light). While it is possible that these slugs use their eyes to detect the shadow of predators, it is more likely that their eyes are primarily their way of keeping their internal clock tuned to day and night.

Flabellina rubrolineata from Papua New Guinea

Since they can't see beyond being able to distinguish light and dark, how do nudibranchs find food or avoid predators? This is done primarily by use of rhinophores (See below) and oral and/or propodial tentacles (See below), additional structures that these animals possess that allow them to sense chemical changes in the water. The rhinophores (aka the nose of the nudibranch) come out of the top of the head of the slug and look a lot like antennae in insects. These structures have special receptors that allow the nudibranch to sense chemical cues in the water, enabling them to find food and avoid predators. Oral and propodial tentacles, however, are more like hands. These structures act as feelers, allowing the slugs to touch the environment around them and determine if the direction they are moving is safe, or if they need to change their path.

Glossodoris symmetricus from Papua New Guinea, with the red rhinophores indicated by a white arrow.

Caloria indica from Papua New Guinea. The white arrows indicate the oral and propodial tentacles.

Though nudibranchs can't see very well, this is obviously not a detriment to their ability to survive. These slugs have evolved multiple adaptations (rhinophores, oral tentacles and propodial tentacles) that allow them to sense their environment, and they have done very well for themselves. So, while we enjoy the beautiful color patterns that these slugs have, we should also admire the amazing adaptations that they have in order to perceive their environment.

by Jessica Goodheart

For more information on (and pictures of) nudibranch rhinophores, see the Sea Slug Forum’s rhinophore page.

Spotlight on Antipatharians (Black Corals)

As the common name implies, black corals produce a skeletal axis that in some species can be jet black in color with a naturally high luster (Fig. 1A). Due to these attributes, black coral has for many centuries been used to make jewelry (Fig. 1C). It is not, however, an ideal substance for jewelry because, unlike precious red and pink coral, it is not stony in nature (i.e., does not contain calcium carbonate); instead, it is entirely organic and consists of concentric layers of protein and chitin (Fig. 1B). Consequently, over time, jewelry made from black coral is subject to drying out and cracking.  In living black corals, however, the protein/chitin nature of the skeleton imparts a degree of flexibility to the thinner branches while increasing the rigidity of the thicker branches and stem which thereby provides greater support for the coral as it grows larger. 

Figure 1. A. Natural, unpolished black coral; B. Cross-section of a black coral branch under polarized light; C. Jewelry prepared with black coral components (B and C adapted from Pax, 1940).

Black corals grow in many different, often tree-like patterns (Fig. 2), some of which look very similar to those of gorgonian corals, the familiar sea fans, sea feathers and sea whips found in shallow waters in subtropical and tropical regions. Colonies of some species can grow to a height of 3 m or more, whereas others may be no more than 10 cm tall. Sometimes the growth pattern of a colony can be highly uniform and highly symmetrical, which is often the case in deep-sea species (Fig. 2, lowermost row).

Figure 2. Colonies of black coral; those in the lowest row are representative of deep-sea species.

The skeleton of black corals is laid down by the overlying living tissue which in large colonies is composed of tens of thousands of tiny polyps each no more than a few millimeters in size (Fig. 3A–B). In most cases it is only with the aid of a hand lens that the individual polyps can be seen (Fig. 3C–D).

Figure 3. A–B. Live colonies of black corals; C–D. Magnified view of A and B respectively, showing the individual polyps. (Photo credit: NOAA/Flower Garden Banks National Marine Sanctuary).

Antipatharian polyps are rather unique among anthozoan cnidarians (with the exception of a few sea anemones) in that they possess only six tentacles (Fig. 4A–E). Most other corals, sea anemones, ceriantharians (tube anemones), and zoanthids (colonial anemones) have more than six tentacles (Fig. 4F–I). The polyps of gorgonians (and other octocorals) have eight tentacles, each of which is pinnately branched like a feather (Fig. 4J).  Polyps of black corals are also different from most other anthozoan groups in that they are not cylindrical in shape but instead are compressed (Fig. 4A), star-shaped (Fig. 4B) or stretched out in the direction of the branch (Fig. 4C). In addition, unlike other cnidarian polyps that usually have a flattened oral disc with the tentacles around the perimeter, black coral polyps do not have an oral disk and the tentacles can arise at different levels on the sides of the polyp.

Figure 4. A–E. Polyps of black corals; F. Sea anemone; G. Cerianthid (tube anemone); H. Polyps of a scleractinian coral); I. Polyps of zoanthid (colonial sea anemone); J. Polyps of an octocoral. Photo credits: C. Goenaga; C. Pittman; NOAA Okeanos Explorer Expeditions; G. Paulay; D. Opresko; M. Nuttall; G. Schmahl; O. Ocaña; NOAA Office of Ocean Exploration and Research.

In living colonies of black corals, the tentacles of the polyps, when fully expanded, can be five or more times the length they are when contracted (Figs 4D and E), and they may be so crowded together that they obscure the individual polyps (Fig. 4D). The surface of the tentacles may appear spotted due to the presence of distinct groupings of stinging cells (nematocysts) (Fig. 4A).

Figure 5. Colonies of living black corals photographed in situ (Photo credits: G. Paulay; P. Humann; S. Kahng; BOEMRE; NOAA/Flower Garden Banks National Marine Sanctuary).

Depending on the species, the color of antipatharian polyps and the surrounding tissue (called coenenchyme) can vary from translucent or whitish to green, yellow, tan, orange, pink, purple or red (Figs. 5–6). Thus, living colonies of black corals do not appear black; it is only after the tissue is removed that the color of the skeleton is visible, and in many species the skeleton is not really black but various shades of brown, with the very thin branches often having a translucent reddish-brown appearance.  

Figure 6. Colonies of deep-sea black corals. (Photo credits: NOAA/Office of Ocean Exploration and Research; Hawaiian Undersea Research Laboratory; NOAA/Olympic Coast National Marine Sanctuary; S. Carolina Dept. Nat. Res.; NOAA/Okeanos Explorer Expeditions).

Another common name for black corals is “thorn corals” because the surface of the skeleton has microscopic spines – although in some species the spines are weakly developed and even absent on the thicker branches as shown in the specimen in Figure 1A. The spines are barely visible to the naked eye – usually appearing only as tiny spots on the surface of the coral. They become more noticeable when viewed with a hand lens (Fig. 7). 

Figure 7. Magnified view of the branches of a black coral showing the skeletal spines.

The spines are rarely more than 0.5 mm in height, and range in shape from being compressed and triangular (when viewed from the side), to conical, thorn-like, blade-like, needle-like, and even blister-like (Fig. 8). In some species they become forked, or multiply lobed at the tip, and even antler-shaped in appearance (Fig. 9A–C)). The spines may be smooth or covered with minute surface features such as fine striations, papillae, or tubercles; these fine details may only be observable under the high magnification of a scanning electron microscope (Fig. 9D–F).

Figure 8. Various types of skeletal spines of black corals.

Antipatharians are exclusively marine and are found in all oceans from the Arctic to the Antarctic. The estimated number of known species is about 280.  Some species of antipatharians can be found living at depths of only a few meters and others as deep as 8600 m, but most occur at depths ranging from about 20 to 1000 m. With a few exceptions, the colonies secrete a basal holdfast that allows them to permanently attach to a hard substrate. 

Our current knowledge, based mainly on shallow-water species, suggests that all black coral species are dioecious, meaning that the polyps in a colony are either all male or all female. The eggs and sperm are released into the water column during mass spawning events similar to those observed in reef corals. The fertilized eggs develop into small ciliated balls of cells called planulae. The planulae of shallow-water species tend to settle on the bottom in locations where light intensity is minimal such as under reef overhangs, in crevices, and in underwater caves, or in areas with high levels of suspended particulate matter. For most species for which information is known the growth of a colony occurs at a rate of one or two centimeters a year. Recently one colony of black coral was estimated to have an age of over 4000 years, making that species one of the oldest living marine organisms.

Figure 9. Skeletal spines of black corals: A. Spine with apical knobs; B. Multiply-forked spine; C. Antler-shaped spines; D. Spine with very fine elongate papillae; E. Spine with coarse papillae; F. Spine with tubercles.

 The classification of the black corals has for many years been complicated by the description of numerous species from poorly preserved and/or incomplete specimens and by the lack of a clearly defined taxonomic hierarchy at the genus and family level. For a long time all species were placed in a single family, the Antipathidae, with many species of very diverse morphologies placed in the single genus Antipathes. For the past 15 years I have been attempting to establish a classification system based on morphological characters that reflect natural relationships within the order.  As a result today seven families of antipatharians are recognized: Antipathidae, Schizopathidae, Cladopathidae, Leiopathidae, Myriopathidae, Aphanipathidae, and Stylopathidae. With some degree of overlap, these families tend to be separated by bathymetric distribution, with two families found in relatively shallow depths, two in intermediate depths, and three most often in the deep-sea. Families are morphologically differentiated on the basis of several taxonomic characters including the number of mesenteries (internal partitions) in the polyps; size and shape of the polyps; size and appearance of the tentacles of the polyps, and the general morphology of the spines. Within the families, genera are differentiated primarily by the growth form of the corallum. Species may be distinguished by one or more of the following features: a) relative length, thickness, density, and arrangement of the branches; b) arrangement of the branches and branchlets; c) size of the polyps; and d) size and morphology of the spines. In recent years the morphologically based classification has been put to the test with new genetic data. The advent of DNA studies has led to a confirmation of many parts of the new classification based on morphology; however, it has also produced several interesting surprises. In one case, three morphologically distinct genera could not be separated by their DNA; in another, a genus long thought to belong to one family based on the internal anatomy of the polyp was found to be associated with another in which it had only superficial morphological similarities; and in a third case, two families recognized on the basis of morphology were shown to be very similar genetically, suggesting that these families may eventually be relegated to subfamily status. 

The primary challenge in working with black corals is that these colonial organisms have relatively few morphological characters, and all of these are highly variable within species, across species, and even across generic lines. As a result, the delineation of species and generic boundaries becomes more difficult as more and more specimens are examined. Although this creates a challenge for the taxonomist, it leads one to suspect that there may be biological mechanisms at work, such as a relatively high degree of natural hybridization and genetic plasticity that has evolved to insure not only the survival of individual species, but the group as a whole.        

One final note. The scientific name for black coral is Antipatharia, derived from the genus name Antipathes, Greek for “against disease”, a reference to the common belief held by peoples in the Far East and in the Indo-Pacific, that corals of this type had mystical curative powers. Amulets of black coral were worn to ward off evil spirits, and there are even stories that black coral was ground into a powder and consumed as a medicine. In reality, because black coral is proteinaceous, it has the potential for just the opposite effect in that it might, in some individuals, produce a severe allergic reaction. There are, however, no reports of black coral jewelry causing a skin rash. Although black coral jewelry is available for purchase in Hawaii and in other localities in the Pacific and even in the Caribbean, it should be noted that all black coral is protected under CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora). Consequently, in most countries the collection of black coral is strictly controlled, and import and export of this material across international borders is strictly prohibited without governmental approval.

By Dennis Opresko

133 Year Overdue Loan Returned to IZ

In April 2016, a Brazilian visitor, Ralf Codeiro, and I initiated a project to revise the octocoral genus Radicipes. The first step was to obtain the type specimens of the eight known species in the genus, two of which are deposited at the NMNH. But, one of them, 5 dry syntypes of Radicipes pleurocristatus Stearns, 1883 (USNM 5685) simply could not be found in the dry type or non-type collection.

Illustration of Radicipes pleurocristatus Stearns, 1883. (Without the actual specimen, this and the written description is all one has to work with.)

It is a long specimen (up to a meter) so the oversized collection was checked, but again no. I e-mailed several octocoral researchers to ask if they might be on loan to them, but with negative results.  As a long shot, I suggested that Cordeiro check the handwritten Radiates catalog for the original cataloging of the specimens in 1883. In that old book, there was a small entry saying that these specimens had been loaned to A. E. Verrill on November 28, 1883. Verrill, a prominent octocoral taxonomist of the nineteenth century, worked at both the MCZ and YPM.  

I sent e-mails to the curators at those two museum, but before a response was received Cordeiro checked the type catalog of YPM and found our specimens cataloged into their museum, with an “other number” as USNM 5685. The syntypes are now being returned 133 years and 5 months later. 

The moral of this story is that if you borrow a specimen from the IZ collection, you had better return it, or we will hunt you down.  But we do have a generous loan extension option.

And the actual specimen arrived today! Home again.

 

By Steve Cairns