Arranging Nautiloids | Catalogue of Organisms

For years, the higher taxonomy of cephalopods was expressed as a division between three subclasses: the Nautiloidea, the Ammonoidea and the Coleoidea. Coleoids were the clade of cephalopods that had lost the external shell, ammonoids were a Mesozoic lineage with complex septa dividing the chambers of the shell, and nautiloids were... the rest. From the tiny, possibly benthic, curved cones of the Cambrian where the class began, to gigantic straight-shelled monsters of the later Palaeozoic, to the modern chambered nautilus, all were lumped together as 'nautiloids'. The nautiloid subclass was explicitly understood to include the ancestors of the others but recognition of more phylogenetically coherent subgroups has been hampered by poor understanding about how the various nautiloid lineages were interrelated. And part of the problem in this regard has been uncertainty about just what features of their fossils we should be paying attention to.

Diorama reconstruction of Beloitoceras oncocerids, from the Burpee Museum.

One factor that has drawn attention in recent years has been the arrangement of muscle scars on the shell. Large muscle attachment scars appear as raised annular elevations on the inside of the shell towards the rear end of the body chamber (in practice, they are more often observed in fossils as depressions on the internal mould). In the living nautilus, the muscles attached to these scars function in the retraction of the head (King & Evans 2019). Modern nautilus possess a pair of large lateral scars in an arrangement that has been labelled 'pleuromyarian'. However, many of the earliest cephalopods possessed a ring of numerous small scars, an arrangement referred to as 'oncomyarian'. Other cephalopods might have scars restricted to the dorsal ('dorsomyarian') or ventral ('ventromyarian') midline.

Primary types of muscle scar in nautiloids, from King & Evans (2019). 'D' and 'V' indicate dorsal and ventral, respectively, and arrows indicate direction of aperture.

Another feature that has been called out has been the structure of the connecting rings around the siphuncle. Shelled cephalopods, you will recall, have the shell divided into chambers separated by septa. Though the bulk of the animal is found in the final body chamber, a fleshy cord called the siphuncle runs back through the remaining chambers. In life, the siphuncle is used to control the levels of fluid in the chambers, which in turn controls the animal's buoyancy. The boundary between the siphuncle and the surrounding chamber is marked a toughened sheath, referred to as the connecting ring. In the modern nautilus, the connecting ring is comprised of two layers, an outer calcareous layer and an inner chitinous layer. In comparable fossils, the latter chitinous layer has decomposed after death so only the outer layer is preserved. However, some extinct cephalopod groups preserve evidence of calcification in the inner as well as the outer layer. Based on the distinction between these two siphuncle types, Mutvei (2015) supported dividing most of the nautiloids between two major lineages, the Nautilosiphonata (with a nautilus-type siphuncle) and the Calciosiphonata (with the internally calcified connecting rings).

A couple of years earlier, the same author (Mutvei 2013) had proposed recognition of a superorder Multiceratoidea for nautiloids that combined multiple muscle scars with a nautilus-type siphuncle. Examples of nautiloid orders with such a combination included the Ellesmeroceratida (small nautiloids with densely placed septa), the Oncoceratida (often short, squat nautiloids) and the Discosorida (similarly squat forms with complex bulging connecting rings). All of these were found in the earlier part of the Palaeozoic with the oncoceratids dieing off in the early Carboniferous. Mutvei (2013) also included the coiled Tarphyceratida and the egg-shaped Ascoceratida in this group. Later, King & Evans (2019) redefined this grouping as the Multiceratia, excluding the Tarphyceratida and Ascoceratida on the grounds that they had ventromyarian rather than oncomyarian muscle scars. Mutvei (2013) suggested that, rather than representing retractor muscles, these smaller repeated scars were associated with an outgrowth of the mantle, either as tentacles or a muscular 'skirt', that was used to capture micro-plankton.

Phylogeny of 'nautiloids' supported by King & Evans (2019). Though not shown on this diagram, the majority of authors have suggested that ammonoids and coleoids are descended from Orthoceratida.

King & Evans (2019) proposed a reclassification of the subclass Nautiloidea between five subclasses defined primarily by muscle structure. Apart from the earliest oncomyarian Plectronoceratia, most 'nautiloids' could be divided between two lineages. On one side were the dorsomyarian Orthoceratia (usually thought to include the ancestors of the ammonoids and coleoids). On the other, the oncomyarian Multiceratia would eventually give rise to the ventromyarian Tarphyceratia which in turn included the ancestors of the pleuromyarian Nautilida. Note that many of the reocognised subclasses (and orders) remain paraphyletic but we are at least approaching a more informative picture of cephalopod evolution than the earlier unceremonious dumping into 'Nautiloidea' (I should probably also remind you that, for various reasons, most invertebrate palaeontologists still don't regard strict monophyly as a taxonomic requirement in and of itself).

The usage of muscle scars and connecting rings as classificatory keys is handicapped by the difficulty of observing them. As internal structures, they each require careful preparation of a specimen to observe. And once you've gotten to a position where you can see them, it seems not to be particularly easy to tell just what you're looking at. As a result, muscle scarring and siphon structure remains undescribed for the majority of nautiloid species. Judging the structure of connecting rings seems to be particularly challenging and some have gone so far as to suggest that purported different structures may be the result of post-mortem taphonomic processes (King & Evans 2019). Nevertheless, what we do know suggests that such features remain reasonably consistent within each of the well-recognised nautiloid orders. And Mutvei's (2015) concept of Calciosiphonata vs Nautilosiphonata does largely line up with King & Evans' (2019) dorsomyarian vs oncomyarian-ventromyarian lineages. There are, of course, some notable exceptions. Whether these will cause the developing structure to collapse, or whether they indicate mistakes in interpretation, only continued research will tell.

REFERENCES

King, A. H., & D. H. Evans. 2019. High-level classification of the nautiloid cephalopods: a proposal for the revision of the Treatise Part K. Swiss Journal of Palaeontology 138: 65–85.

Mutvei, H. 2013. Characterization of nautiloid orders Ellesmerocerida, Oncocerida, Tarphycerida, Discosorida and Ascocerida: new superorder Multiceratoidea. GFF 135 (2): 171–183.

Mutvei, H. 2015. Characterization of two new superorders Nautilosiphonata and Calciosiphonata and a new order Cyrtocerinida of the subclass Nautiloidea; siphuncular structure in the Ordovician nautiloid Bathmoceras (Cephalopoda). GFF 137 (3): 164–174.

Terrifying big spiders soon in the DMV? Meet the Jorō Spider, Trichonephila clavata, and its cousin the Golden Silk Spider, Trichonephila clavipes

 

People ask, “How will I recognize the Jorō spider?” The large web and striking color patterns of this very large spider make it pretty easy to identify. Image credit: Mary Nouri

 

A fascinating new study by entomologists Andrew Davis and Benjamin Frick at the University of Georgia produced a firestorm of interest in the Jorō spider over the past week or so. Jorō is a native to eastern Asia (Japan, China, Korea, and Taiwan). Although it has been known in Georgia since 2013, it is now spreading rapidly in southeastern states to many counties in Georgia, the Carolinas, Tennessee, and Oklahoma. Jorō joined its cousin the golden silk spider, Trichonephila clavipes, which has been in the US for more than a century and now occupies parts of Florida, several other southeastern states, and even rarely makes an appearance as far north as Pennsylvania. The golden silk spider, a native of Central and South America, has remained mostly bottled up in the south likely due to its inability to tolerate cooler temperatures further north. However, the recent study by Davis and Frick found Jorō spiders to have a higher metabolism, supported by a faster heart rate, and a better ability to tolerate freezing temperatures than their warm-loving cousin. These traits combined with more rapid development enable Jorō to complete its life cycle rapidly, before chilly temperatures bring its seasonal development to an end. Davis and Frick suggest that this suite of adaptations may enable Jorō to escape the relative warmth of the south and expand its range northward along the eastern seaboard, whereas the golden silk spider may remain largely trapped in warmer southern states.

While these findings support the potential for a northward range expansion, there is much yet to be learned about how successfully Jorō will survive northern winters. But as our nation and world warm, we have seen several southern species of insects expand their range to higher latitudes and altitudes. We also don’t know how rapidly range expansion will occur. In nature the typical mode of dispersal of many spiders, including Jorō, is by aerial dispersal of spiderlings. They balloon on strands of silk like Charlotte's babies in the book ‘Charlotte’s Web’. By the way, ballooning likely has given rise to the more spectacular moniker for Jorō, the “parachute spider". No, they really will not rain down on you from airplanes. Long distance transit by Jorō probably depends on human assistance. Adults and their spawn are good hitchhikers. Jorō may have entered this country as an inseminated and gravid female or as an egg case stowaway in a cargo container from Asia. Their arrival in the DMV is likely to take several years by natural means, but a new introduction at a local port or a human assist in vehicles from the south could accelerate their arrival.

The bite of Jorō will be terrible and painful, right? Nah, according to expert Rick Hoebeke, the risks to humans and pets are small due to the puny size of Jorō’s fangs, which are unlikely to pierce our skin. I have visited Joro's cousin, the golden silk spider, up close and personal in the rainforest of Costa Rica and found the large females to be completely non-aggressive. These spiders are passive hunters that build enormous webs, larger than a meter in diameter, to capture prey snared by silk.

In the rainforests of Costa Rica and landscapes in the southeastern United States, golden silk spiders build webs exceeding a meter in diameter. Hair tufts on the 1st, 2nd, and 4th pairs of legs distinguish golden silk spiders from Jorō spiders. Watch as a female manipulates the remains of an unrecognizable victim while a male golden silk spider observes from a safe distance.

The underside of the Jorō spider has striking red markings. Image credit: Sarah Morgan

For arachnophobes, Jorō spiders may be scary but for arachnophiles these are beautiful spiders which may provide important ecosystem services, including biological control of crop pests such as brown marmorated stink bugs or spotted lanternflies, with which they have an ancient association in their native range in Asia. Jorō spiders may be like Hannibal Lecter "having an old friend over for dinner" when they meet the stink bug or lanternfly for the first time here in the US. Large spiders like these may also become juicy prey items for feathered and non-feathered reptiles. As with all non-native species that arrive on our shores, it is difficult to predict what impact they will have on our ecosystems but experts suggest that beyond their somewhat scary mien, and maybe giving our indigenous large orb weavers like the black and yellow garden spider a run for their money, any direct impact on humans and pets will be minimal. 

One final tidbit about Jorō: in Japanese folklore Jorō is a shapeshifter known as Jorō-gumo. Jorō-gumo turns into a beautiful woman, seduces men, binds them with silk, and devours them. Yikes, sounds like a bad date to me.

Acknowledgements

Bug of the Week thanks Rick Hoebeke for identifying Jorō as it arrived in the US and for providing insights into the ways of these large beautiful spiders. We also thank Mary Nouri and Sarah Morgan for sharing their great images of Jorō. Fascinating studies entitled “Physiological evaluation of newly invasive jorō spiders (Trichonephila clavata) in the southeastern USA compared to their naturalized cousin, Trichonephila clavipes” by Andrew K. Davis and Benjamin L. Frick, “Nephila clavata L Koch, the Jorō Spider of East Asia, newly recorded from North America (Araneae: Nephilidae)” by E. Richard Hoebeke, Wesley Huffmaster, and Byron J Freeman, and “The Life Cycle, Habitat and Variation in Selected Web Parameters in the Spider, Nephila clavipes Koch (Araneidae)” by Clovis W. Moore provided the inspiration for this story and details surrounding the stars of this episode.

To see other large orb weavers and differentiate them from the Jorō spider, please click on this link: https://resources.ipmcenters.org/view/resource.cfm?rid=27877

To hear more about the Jorō spider, please click on this link: https://wamu.org/story/22/03/11/joro-spiders-relatively-harmless-in-dc/

In Honour of Amblyseius | Catalogue of Organisms

At this point in time, the Phytoseiidae are one of the most intensely studied families of mites. They are the only group of mesostigmatan mites to have significantly diversified among the foliar environment (on and around plant leaves) where they are mostly predators on other small invertebrates. The taxonomic history of phytoseiids is storied and complex but one taxon that has been consistently recognised as a major part of the family is the genus Amblyseius.

Swirski mite Amblyseius swirskii, from here.

When reviewed by Chant & McMurtry in 2004, Amblyseius was a sizeable assemblage of close to 350 known species (I quite expect that number to have expanded by now). Species of Amblyseius are lightly sclerotised, mostly pale in colour, and usually have a smooth shield covering most of the dorsum. The genus is characterised by the presence of eighteen or nineteen pairs of setae on the dorsum of the idiosoma (the central body) with three sublateral pairs being particularly long: one about the level of the third pair of legs (referred to as the s4 pair) and the other two towards the rear of the body. Except for a few pairs forward of the s4 setae, the remaining dorsal setae are all minute.

The primary focus of human interest in phytoseiids has been their role as predators of crop pests. I described some of the ways in which phytoseiids have been commercially utilised in an earlier post. Species used in this way include several Amblyseius though matters are complicated slightly by changes in taxonomy (for instance, one species which has been widely traded as Amblyseius cucumeris is now placed in the genus Neoseiulus). One of the most widely used of the commercial phytoseiids in recent years has been Amblyseius swirskii, commonly known as the Swirski mite (E. Swirski being an acarologist after whom the species was named). This species was first described in 1962 from almond trees in Israel and subsequently identified from a wide range of plant and crop species. Its history in pest control has been described in detail by Calvo et al. (2015).

The Swirski mite feeds on a range of prey, including mite, thrips and whitefly species, as well as on pollen and micro-fungi. It was first promoted as a commercial control for silverleaf whitefly Bemisia tabaci in the early 2000s. However, it did not get taken up in a big way until media publicity about pesticide residues on capsicum crops in Spain led to a crash in demand. Farmers in that country were forced to look for alternative means of pest control and found great success with A. swirskii (previous attempts to use the cooler-clime preferring Neoseiulus cucumeris in Spain had not been promising). Since then, the Swirski mite has been adopted in numerous countries for use on a range of crops to control various pests such as western flower thrips Frankliniella occidentalis. Because of its ability to grow and thrive on non-insect foods, including artificial diets, this mite is easily cultured commercially. It may also be released on crops before pest infestations develop, building up numbers on a diet of pollen until suitable prey presents itself. For the same reason, Swirski mite populations do not crash before pest control is complete. Overall, a remarkable success and a prime example of the value of Amblyseius species to mankind.

REFERENCES

Calvo, F. J., M. Knapp, Y. M. van Houten, H. Hoogerbrugge & J. E. Belda. 2015. Amblyseius swirskii: what made this predatory mite such a successful biocontrol agent? Experimental and Applied Acarology 65: 419–433.

Chant, D. A., & J. A. McMurtry. 2004. A review of the subfamily Amblyseiinae Muma (Acari: Phytoseiidae): part III. The tribe Amblyseiini Wainstein, subtribe Amblyseiina n. subtribe. International Journal of Acarology 30 (3): 171–228.

Some great news for western migratory Monarch butterflies, Danaus plexippus

 

Some good news as western monarch butterflies make a comeback in the winter of 2021-2022.

 

Last August we recapped some dire news concerning the plight of migratory monarch butterflies, particularly the scary decline of monarchs on the west coast of the US.  In 2014, Bug of the Week communed with thousands of western monarchs in Pacific Grove, CA, also known as “Butterfly Town, USA”. Six years later in 2020, the annual winter monarch count in the west plunged from tens of thousands to a shocking 1,914, a decline of more than 99.9% from historic levels. Many believed it might be too late to save the western migratory monarchs. Attempts to have monarchs declared an endangered species by the US Fish and Wildlife Service failed in December of 2020 as resources were needed to focus on "higher-priority listing actions" according to agency officials. In a remarkable and not fully understood turnabout, populations of western monarchs have increased more than 100-fold to almost 250,000 overwintering butterflies reported in the current annual winter monarch census completed in January 2022. This is really encouraging news and Emma Pelton, conservation biologist with the Xerces Society, called the upswing “magnificent”.   

In the winter of 2021-2022 the Monarch Sanctuary in Pacific Grove had an encouraging complement of 10,000 overwintering monarchs.

But what is behind this remarkable “bounce” in the western monarch population? Alissa Greenberg of NOVA provided a fascinating peek into possible explanations for this phenomenon in her interview with experts of monarch biology and ecology. Several potential hypotheses were advanced. Drs. Louie Yang and Art Shapiro of UC Davis and Elisabeth Crone of Tufts University propose that a series of “fortunate events” may have conspired in the spring and summer of 2021 to boost populations of monarchs throughout their range. These include a fortuitous match of the spring arrival of monarchs to high quality patches of milkweeds in peak condition to support the growth and development of monarch caterpillars. High food quality translates into higher survival of robust caterpillars that develop into fecund adults, which boost monarch populations. Dr. Shapiro adds that drought in the west may have reduced planting of many crops, thereby reducing attendant pesticide applications harmful to monarch butterflies and their young. An additional hypothesis advanced by entomologists and conservation biologists posits a population supplement of migratory butterflies as urban and suburban monarchs spawned on milkweeds planted by butterfly enthusiasts joined those from natural and rural settings. Yet another possibility advances the notion that some peripatetic monarchs from the larger eastern migration hopped across the country to join their western counterparts. As author Greenberg points out, further research is needed to confirm or infirm these ideas and it is likely that several mechanisms acting in concert underlie this remarkable “bounce” in populations of western migratory monarchs.

Along the California coast monarchs cluster on pine branches and rest during cool, moist mornings. As the morning mist clears, monarchs bask in the mid-day sun to warm their bodies. By afternoon with flight muscles sufficiently warmed, they take wing to visit nearby blossoms. In 2014 when these monarchs were filmed in Pacific Grove, western monarch populations were similar to those in the winter of 2021-2022. This spring why not plant some milkweeds to feed monarch caterpillars? Milkweeds also provide a nectar source for adults.

So, what can be done to help save these unique and charismatic migratory creatures? Globally, mitigating climate change, reducing unnecessary pesticide use, and conserving resources and habitats for wildlife will help. Locally, providing milkweeds for monarch caterpillars and nectar plants for adults can facilitate reproduction and survival of monarchs. Regional references for milkweed plants can be found at this link https://xerces.org/milkweed and references for monarch nectar plants can be found at this link https://xerces.org/monarchs/monarch-nectar-plant-guides  For great tips to create your homegrown monarch habitat, click on this excellent story about University of Kentucky entomologists Adam Baker and Dan Potter, who evaluated several elements of garden design to better support the needs of monarchs:  https://news.ca.uky.edu/article/uk-research-shows-how-build-more-effective-monarch-butterfly-gardens 

Be sure to consult a reference to learn what milkweeds work well in your geographic region. Here in Maryland, species including common milkweed, Asclepias syriaca, swamp milkweed, Asclepias incarnata, and butterfly weed, Asclepias tuberosa, are good choices. In the waning weeks of winter, monarchs will depart their winter redoubts on the west coast and abandon the montane fir forests of Mexico to begin their long journeys northward. With days getting longer, it is time to plan your gardens and include appropriate milkweeds and nectar plants to support the monarchs. We have a role to play in conserving these remarkable wanderers.

Acknowledgements

Please visit the excellent story by Alissa Greenberg of NOVA to learn more about the renaissance of western monarchs at this link: https://www.pbs.org/wgbh/nova/article/western-monarch-population-growth-2021/

To learn more about monarchs, their migrations and perils, and how to conserve them, please visit the following websites:

https://xerces.org/monarchs/western-monarch-conservation

https://xerces.org/monarchs/eastern-monarch-conservation

https://xerces.org/blog/monarch-numbers-from-mexico-point-to-declining-population

https://www.nationalgeographic.com/animals/article/monarch-butterflies-near-extinction

https://www.nationalgeographic.com/animals/article/monarch-butterflies-risk-extinction-climate-change

https://www.washingtonpost.com/world/the_americas/climate-change-is-playing-havoc-with-mexicos-monarch-butterfly-migration/2019/12/23/e60c1e0e-21ab-11ea-b034-de7dc2b5199b_story.html

http://www.monarchwatch.org/index.html   

http://www.eeb.cornell.edu/agrawal/2017/02/10/monarch-population-size-over-winter-2016-2017-announced/

By the Light of the Pony | Catalogue of Organisms

Light-emitting organs have evolved in many different species of marine fish. For the greater part, they are associated with inhabitants of the deep sea, the twilight and midnight zones beyond the reach of celestial light. Light production by species found in shallow waters is much less common. Nevertheless, one particularly notable radiation of near-surface glowers is the ponyfishes of the family Leiognathidae.

Leiognathus equulus, copyright Sahat Ratmuangkhwang.

Ponyfishes are small, mostly silvery fishes found in coastal and brackish waters in tropical regions of the Indo-West Pacific. The largest ponyfishes grow to about 25 cm in length but most species are much smaller (Woodland et al. 2002). They live in large schools that forage near the surface at night, descending close to the bottom sediment during the day. Why these animals are referred to as 'ponyfishes', I have no idea (perhaps the head is meant to look a bit pony-like?) An alternative vernacular name of 'slipmouth' makes a lot more sense as these fish have highly extensible jaws that can be used to snipe prey out of the water. A groove along the top of the skull allows for reception of a long, mobile premaxilla, supporting the mouth as an elongate tube when extended. Most ponyfishes are planktivores with simple, minute teeth in the jaw and the mouth extending horizontally. Species of the genus Deveximentum have the mouth tilted obliquely at rest so that it stretches upwards when extended. Members of the genus Gazza are piscivores when mature, feeding on other fish, and possess a pair of large caniniform teeth in each of the upper and lower jaws to hold their prey (James 1975).

Ponyishes are also notable for their elaborate light-producing organs. In most bioluminescent fishes, the photophores sit on or close to the skin surface but in leiognathids it is an internal outgrowth of the gut. A cavity around the end of the oesophagus houses colonies of bioluminescent bacteria, usually the species Photobacterium leiognathi. This light organ sits alongside or projects into the gas bladder which has a reflective internal coating. In many species, patches of scale-less, translucent skin allow the transmitted light to shine forth brightly. Muscular 'shutters' associated with the light organ allow the fish to control light transmission more directly (Woodland et al. 2002).

Photopectoralis bindus, copyright D. G. R. Wiadnya.

In a review of ponyfish taxonomy by James (1975), no mention was made of the light-emitting organ or many of its associated structures (though reference was made to the absence of scales on certain parts of the body). With the exceptions of the distinctive genera Gazza and Deveximentum, ponyfishes were assigned to a broad genus Leiognathus. Since then, variations in the structure of the light organ have been recognised as taxonomically significant, allowing the recognition of several genera divided between two subfamilies Leiognathinae and Gazzinae (Chakrabarty et al. 2011). Leiognathinae is defined by plesiomorphic characters and is likely to be paraphyletic to Gazzinae (Sparks & Chakrabarty 2015).

Because of the nocturnal habits of ponyfish and the delicacy of the light-emitting structures, our understanding of how light production functions in Leiognathidae remains somewhat limited. In Leiognathinae and females of Gazzinae, the light organ is relatively small and the external body surface lacks translucent patches. For the most part, light is expressed in these individuals as a uniform ventral glow that probably functions as counter-illumination (the light from the venter prevents the fish from appearing as a silhouette against light from the water surface to predators swimming below). Alternatively, light may be flashed to warn school-mates of danger. In males of Gazzinae, conversely, the light organ is enlarged relative to females and associated with translucent 'windows'. The shape of the organ and the arrangement of the 'windows' is a primary factor in distinguishing genera. Rhythmic flashing of light has been observed in males of many gazzine species and is probably characteristic of the group as a whole. Woodland et al. (2002) observed a school of several hundred Eubleekeria splendens flashing their lights synchronously shortly after nightfall. The exact function of such displays is uncertain, whether in courtship displays, co-ordinating school movements, attracting prey or dissuading predators. The sexually dimorphic nature of the light organ system, together with its species-specific expression, might seem to favour the first of these options but it should be noted that they are not all mutually exclusive.

Despite their small size, ponyfishes are often significant food fish for people living in areas where they are found. Thanks to their schooling behaviour, they are often a major component of dredge catches. In the Philippines, they are used for making bagoong, a fermented fish paste. In other places, they may be cooked whole after cleaning. The glow, sadly, does not survive the process.

REFERENCES

Chakrabarty, P., M. P. Davis, W. L. Smith, R. Berquist, K. M. Gledhill, L. R. Frank & J. S. Sparks. 2011. Evolution of the light organ system in ponyfishes (Teleostei: Leiognathidae). Journal of Morphology 272: 704–721.

James, P. S. B. R. 1975. A systematic review of the fishes of the family Leiognathidae. J. Mar. Biol. Ass. India 17 (1): 138–172.

Sparks, J. S., & P. Chakrabarty. 2015. Description of a new genus of ponyfishes (Teleostei: Leiognathidae), with a review of the current generic-level composition of the family. Zootaxa 3947 (2): 181–190.

Woodland, D. J., A. S. Cabanban, V. M. Taylor & R. J. Taylor. 2002. A synchronized rhythmic flashing light display by schooling Leiognathus splendens (Leiognathidae: Perciformes). Marine and Freshwater Research 53: 159–162.