Stomatopod Larvae Research Articles

Haline Tolerance of Stomatopod (Crustacea) Larvae and Pelagic Dispersal of Two Common Species in the Western Atlantic

AbstractPelagic larval stages play a critical role in the dynamics of marine populations since they are the main way of dispersal and habitat colonization. Here, we examined the larval dispersal pathways of two common stomatopod species in the western Atlantic: Squilla empusa and Lysiosquilla scabricauda. To complement this goal, we also analyzed the haline tolerance of the stomatopod larvae collected in an estuary from the southern Gulf of Mexico. Larval dispersal was simulated using a Lagrangian particle‐tracking module coupled to the Global HYCOM model and consisted of releasing 100 passive particles from each starting site. Results indicated a high level of larval retention in the west Florida shelf and over the narrow western shelf of the Gulf of Mexico. In the South Atlantic Bight, Central America, and northern South America the larval transport was almost unidirectional following the pattern of currents. Generally, connections were among nearby sites, but long‐distance transport can also occur when larvae are trapped by great high‐speed currents. Retention of larvae and connection with neighboring sites were due to local atmospheric and hydrological conditions. During fieldwork, we found two kinds of larvae: antizoea and alima. Morphological characteristics of the antizoea correspond to the superfamily Lysiosquilloidea, and those of the alima, with the superfamily Squilloidea. The antizoea larvae were found in salinity values as low as 21.9 psu, while the alima were at 23.2 psu. Salinity tolerances and dispersal potential of larvae indicate a high level of colonization of new habitats and a broad intrusion into the estuaries.

Multiple island effects shape oceanographic processes and zooplankton size spectra off an oceanic archipelago in the Tropical Atlantic

Pelagic ecosystems around tropical oceanic islands are considered oases of high plankton biomass in the middle of oligotrophic “blue deserts”. To understand the dynamics of such a pelagic ecosystem, we used CTD and ADCP data and zooplankton samples taken from the waters off the remote Fernando de Noronha Archipelago (FNA), Tropical Atlantic. We analyzed how the flow and island topography interactions influence the spatial variability of chlorophyll-a fluorescence and zooplankton abundance, biovolume, and normalized biovolume size spectra (NBSS). We used a 500-μm mesh bongo net to obtain plankton samples in July and August 2010 in areas upstream and downstream of FNA. Zooplankton samples were analyzed with a ZooScan device. Chlorophyll-a peaks and a rise in thermocline indicated a topographic uplift and turbulence downstream of the island, i.e., the “Island Mass Effect”. The NBSS presented a mean slope of −1.19 ± 0.28, and a mean intercept of 3.98 ± 0.87. There were no significant differences in NBSS slopes and intercepts between upstream and downstream areas. Nevertheless, zooplankton and decapod community structures were significantly different between areas: meroplanktonic communities showed higher abundances and biovolumes downstream (p < 0.05). Zoeae of stenopodid cleaner shrimps, anomuran and brachyuran crabs, and fish eggs were significantly more abundant downstream, indicating a “Larval Island Effect”. Distinct peaks in size spectra due to teleost eggs and decapod larvae, downstream of FNA, also indicated a Larval Island Effect. Upstream of the island, there was a higher abundance of gelatinous organisms, holoplanktonic decapods, and advanced stages of brachyuran crabs (“Upstream Island Effect”). Also, copepods, gelatinous organisms, large-sized “other crustaceans” (e.g., euphausiids, amphipods, stomatopod larvae, mysids, etc.), teleost eggs, and stenopodids caused abundance peaks in the size spectra upstream. Our study highlights the need for careful management and conservation of parental spawning stocks of fishes and macroinvertebrates surrounding tropical oceanic islands.

Hawaiian larval stomatopods: molecular and morphological diversity

Estimating stomatopod species diversity using morphology alone has long been difficult; though over 450 species have been described, new species are still being discovered regularly despite the cryptic behaviors of adults. However, the larvae of stomatopods are more easily obtained due to their pelagic habitat, and have been the focus of recent studies of diversity. Studies of morphological diversity describe both conserved and divergent traits in larval stomatopods, but generally cannot be linked to a particular species. Conversely, genetic studies of stomatopod larvae using DNA barcoding can be used to estimate species diversity, but are generally not linked to known species by analyses of morphological characters. Here we combine these two approaches, larval morphology and genetics, to estimate stomatopod species diversity in the Hawaiian Islands. Over 22 operational taxonomic units (OTUs) were identified genetically, corresponding to 20 characterized morphological types. Species from three major superfamilies of stomatopod were identified: Squilloidea (4 OTUs, 3 morphotypes), Gonodactyloidea (9, 8), and Lysiosquilloidea (6, 7). Among these, lysiosquilloids were more diverse based on larval morphotypes and OTUs as compared to previously documented Hawaiian species (3), while squilloids had a lower diversity of species represented by collected larvae as compared to the seven species previously documented. Two OTUs / morphotypes could not be identified to superfamily as their molecular and morphological features did not closely match any available information, suggesting they belong to poorly sampled superfamilies. The pseudosquillid, Pseudosquillana richeri, was discovered for the first time from Hawai'i. This study contributes an updated estimate for Hawaiian stomatopod diversity for a total of 24 documented species, provides references for identification of larval stomatopods across the three major superfamilies, and emphasizes the lack of knowledge of species diversity in more cryptic stomatopod superfamilies, such as Lysiosquilloidea.

Morphological observations and molecular confirmation of larvae ofLevisquilla inermis(Crustacea: Stomatopoda) from the Seto Inland Sea

AbstractMantis shrimps are commercially important crustaceans in many areas of the world. In contrast to the relatively common studies of adults, limited studies have been attempted of larvae because of a lack of identification keys. The objectives of this study were two-fold: (1) to link wild-caught larval specimens from the Seto Inland Sea to a certain species and (2) to present a detailed morphological description of the last larval stage. The resulting molecular phylogenetic tree based on 16S rRNA gene sequences strongly implies that our larval specimens were linked toLevisquilla inermis, which was barcoded from a newly collected adult specimen with a morphological identification. K2P genetic divergence was found to be 0% among the larval and adult specimens. The congeneric speciesL. jurichiwas the sister group of theL. inermiscluster, but the K2P distance between them was 3.4%, and it was considered a distinct species. Morphological observations provided five major distinguishing characteristics of the last-stage larva ofL. inermis: (1) propodus of second maxilliped with three basal spines, (2) all five pleopods possessing an appendix interna with cincinnuli, (3) exopod of uropod longer than the endopod, (4) distal margin of the exopod of the uropod reaching the lateral tooth of telson, and (5) telson with nine intermediate denticles. Overall, our results reveal the importance of combining molecular and morphological analyses for solving stomatopod larval identification. This finding can be used to support and facilitate future research on the taxonomy and biodiversity of stomatopod larvae.

To the light side: molecular diversity and morphology of stomatopod larvae and juveniles (Crustacea: Malacostraca: Stomatopoda) from crustose coralline algal reefs in Taiwan

Biology of planktonic stomatopod larvae has long remained poorly understood and often considered “black boxes” in life history studies. From coralline crustose algal (CCA) reefs at Datan, Taoyuan, Taiwan, using light traps recently designed, we collected considerable number of stomatopod larvae and juveniles. Applying DNA barcoding techniques using mitochondrial cytochrome oxidase I (COI) and 16S ribosomal RNA (16S rRNA) gene sequences, 14 morphotypes were revealed to represent 12 distinct species, seven of which identified to species level by comparing against reference sequences available from online source (GenBank), whereas the other five do not cluster with any known sequences. All stomatopod larvae and juveniles were described and illustrated. We report Manningia pilaensis (De Man, 1888) and Levisquilla jurichi (Makarov, 1979) as new records of the stomatopod fauna of Taiwan and confirm the validity of Lysiosquillina maculata (Fabricius, 1793). Based on material we acquired from light traps, which include propelagic antizoea larvae (of L. maculata), and also postlarval and juvenile forms (of various squillid species), both positively phototactic, indicating the current understanding of negative-positive-negative phototactic tendency from early planktonic to postlarval stages through the development of stomatopod larvae, might not be as distinct as previously described.

Using larval barcoding to estimate stomatopod species richness at Lizard Island, Australia for conservation monitoring

Stomatopods (Crustacea, Stomatopoda) are well studied for their aggressive behavior and unique visual system as well as their commercial importance in Asian and European countries. Like many crustaceans, stomatopods undergo indirect development, passing though several larval stages before reaching maturity. Adult stomatopods can be difficult to catch due to their inaccessible habitats and cryptic coloration. By sampling larvae from the planktonic community, less effort is required to obtain accurate measures of species richness within a region. Stomatopod larvae were collected between 2006 and 2015 from the waters around the Lizard Island reef platform in Eastern Australia. Cytochrome oxidase I (COI) mitochondrial DNA sequences were generated from each larval sample and compared to a database of COI sequences tied to adult specimens. Of the 20 species collected from Lizard Island as adults which have COI data available, 18 species were identified from larval sampling. One additional species identified from larval samples, Busquilla plantei, was previously unknown from Lizard Island. Nine larval OTUs were found not to match any published adult sequences. Sampling larval stomatopod populations provides a comparable picture of the adult population to benthic sampling methods and may include species richness beyond what is measurable by sampling adult populations.

Are tropical coastal reefs sinks or sources of mesozooplankton? A case study in a Brazilian marine protected area

In spite of the paramount ecological and socioeconomic relevance of tropical reef ecosystems, the dynamics of their meroplankton abundance remain poorly characterized. The small-scale distribution and detailed analysis of individual biomass of mesozooplankton were studied in the coastal reefs of Tamandare (Brazil). Mesozooplankton (> 300 μm) was collected during nocturnal ebb tides at new moon, using three different devices to sample at three different environments: a standard ring net that was towed at subsurface, the Channel Midwater Neuston Net that collected at midwater in channels between patch reefs and the Reef Edge Net that captured organisms that are washed by ebb currents from reef tops toward the reef edge. Samples were analyzed using a ZooScan to obtain abundances and biovolume of each taxonomic group. Specific biomass measurements were taken to obtain allometric equations used to calculate zooplankton biomass from biovolume. The mesozooplankton were significantly more abundant at subsurface and at the reef edge compared to channel environments. The high abundance of organisms at reef edges suggests a low predation pressure on zooplankton at near-bottom areas, since the reefs of Tamandare present a low coverage of planktivorous corals, being dominated by macroalgae. These results show that rather than sinks these ecosystems may be considered important sources of zooplankton available for planktivorous species. Regarding zooplankton composition, we found large amounts of initial stages of meroplanktonic larvae and newly hatched fish eggs, which presented consistently greater abundances compared to holoplankton and emergent benthic taxa. Decapod larvae were the most abundant group of the meroplankton, but cirripedian nauplii, stomatopod larvae, fish larvae and fish eggs were also abundant. More than 50% of the total biomass was due to meroplankton taxa, mainly composed of decapod larvae. This study indicates that the contribution of meroplankton to mesozooplankton composition and biomass off tropical reefs may have been underestimated.

DNA barcoding reveals underestimated species diversity of mantis shrimp larvae (stomatopods) in Banten Bay, Indonesia

Abstract. Abinawanto, Intan MDB, Wardhana W, Bowolaksono A. 2019. DNA barcoding reveals species diversity of mantis shrimp larvae (stomatopods) from Banten Bay, Indonesia. Biodiversitas 20: 1758-1763. Larvae of stomatopods can be morphologically identified by linking between larval and adult form, but it's difficult applied in the laboratory because of requirement of condition to rearing larvae collected either from plankton, or spawning adults in the laboratory. Molecular methods are the alternative approach to gather accurate taxonomic identification. One of molecular methods is DNA barcoding based upon sequence diversity in cytochrome c oxidase subunit 1 (COI). Research on stomatopod larvae diversity and distribution at six stations in Banten Bay has been studied from October 2013 to March 2014. This study was conducted to identify the diversity of stomatopod larvae through DNA barcoding and also to examine the distribution of stomatopod larvae in Banten Bay. DNA barcoding was used to identify mantis shrimp larvae in Banten Bay, Indonesia. Partial mitochondrial COI were obtained for 37 larvae, revealing five distinct molecular operational taxonomic units (MOTUs). All MOTUs distinctively fell into Squillidea clade. Two Molecular Operational Taxonomic Units, MOTUs were successfully identified to species level (i.e. Anchisquilla fasciata), while three others remained identified to genus level (i.e. Stomatopoda spp). The intraspecific variation of COI ranged from 0% to 3.1% (Kimura 2-parameter distance), whereas interspecific divergence ranged from 5.9% to 20.4%. These results imply that COI genes are suitable for species identification of stomatopod larvae in this area, though the number of unidentified species was higher than the identified ones. This is likely because of the limited database in GenBank. In addition, the two identified species represents new records for this area, suggesting that the mantis shrimp in the area have been underestimated based on traditional biodiversity measures. We recommend to develop a taxonomically-comprehensive DNA barcoding database to improve the accuracy and feasibility of using DNA barcoding for species identification of Indonesia mantis shrimps.

Morphology of stomatopod larvae from National Parks: Sistema Arrecifal Veracruzano and Arrecife Puerto Morelos, Mexico

ABSTRACT The present study provides information on the morphology of stomatopod larvae found in two different reef systems which are also considered national parks: the Sistema Arrecifal Veracruzano (SAVNP) and Arrecife Puerto Morelos (APMNP). Zooplankton samples were collected at 26 stations of the SAVNP and four stations of the APMNP. Stomatopod larvae were identified and classified by their larval stage. We found representatives of three stomatopod superfamilies: the superfamily Gonodactyloidea Giesbrecht, 1910 was represented by Neogonodactylus oerstedii (Hansen, 1895), Neogonodactylus wennerae Manning and Heard, 1997, and Pseudosquillidae genus and species indeterminate; the superfamily Lysiosquilloidea Giesbrecht, 1910 was represented by Lysiosquilloidea genus and species indeterminate, Lysiosquilla sp., Lysiosquilla scabricauda (Lamarck, 1818) and Nannosquilla adkisoni Camp and Manning, 1982; the superfamily Squilloidea was represented by larvae of Alima neptuni (Linnaeus, 1768), Squilla spp., and Squilla empusa Say, 1818. We were able to identify and describe four stages of larval development for representatives of these superfamilies. This is the first study describing several stages of larval development of different species of the stomatopods from the Gulf of Mexico and Caribbean Sea.

Two visual systems in one eyestalk: The unusual optic lobe metamorphosis in the stomatopod Alima pacifica.

The compound eyes of adult stomatopod crustaceans have two to six ommatidial rows at the equator, called the midband, that are often specialized for color and polarization vision. Beneath the retina, this midband specialization is represented as enlarged optic lobe lamina cartridges and a hernia-like expansion in the medulla. We studied how the optic lobe transforms from the larvae, which possess typical crustacean larval compound eyes without a specialized midband, through metamorphosis into the adults with the midband in a two midband-row species Alima pacifica. Using histological staining, immunolabeling, and 3D reconstruction, we show that the last-stage stomatopod larvae possess double-retina eyes, in which the developing adult visual system forms adjacent to, but separate from, the larval visual system. Beneath the two retinas, the optic lobe also contains two sets of optic neuropils, comprising of a larval lamina, medulla, and lobula, as well as an adult lamina, medulla, and lobula. The larval eye and all larval optic neuropils degenerate and disappear approximately a week after metamorphosis. In stomatopods, the unique adult visual system and all optic neuropils develop alongside the larval system in the eyestalk of last-stage larvae, where two visual systems and two independent visual processing pathways coexist. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 78: 3-14, 2018.

Crustacean Larvae-Vision in the Plankton.

We review the visual systems of crustacean larvae, concentrating on the compound eyes of decapod and stomatopod larvae as well as the functional and behavioral aspects of their vision. Larval compound eyes of these macrurans are all built on fundamentally the same optical plan, the transparent apposition eye, which is eminently suitable for modification into the abundantly diverse optical systems of the adults. Many of these eyes contain a layer of reflective structures overlying the retina that produces a counterilluminating eyeshine, so they are unique in being camouflaged both by their transparency and by their reflection of light spectrally similar to background light to conceal the opaque retina. Besides the pair of compound eyes, at least some crustacean larvae have a non-imaging photoreceptor system based on a naupliar eye and possibly other frontal eyes. Larval compound-eye photoreceptors send axons to a large and well-developed optic lobe consisting of a series of neuropils that are similar to those of adult crustaceans and insects, implying sophisticated analysis of visual stimuli. The visual system fosters a number of advanced and flexible behaviors that permit crustacean larvae to survive extended periods in the plankton and allows them to reach acceptable adult habitats, within which to metamorphose.

Functional morphology of giant mole crab larvae: a possible case of defensive enrollment.

BackgroundMole crabs (Hippidae) are morphologically distinct animals within Meiura, the “short-tailed” crustaceans. More precisely, Hippidae is an ingroup of Anomala, the group which includes squat lobsters, hermit crabs, and numerous “false” crabs. Within Meiura, Anomala is the sister group to Brachyura, which includes all true crabs. Most meiuran crustaceans develop through two specific larval phases. The first, pelagic one is the zoea phase, which is followed by the transitory megalopa phase (only one stage). Zoea larvae are rather small, usually having a total size of only a few millimeters. Zoea larvae of some hippidan species grow significantly larger, up to 15 mm in size, making them the largest known zoea larvae of all anomalan, and probably all meiuran, crustaceans. It has been suggested that such giant larvae may be adapted to a specific defensive strategy; i.e., enrollment. However, to date such giant larvae represent a rarity.MethodsEight specimens of large-sized hippidan larvae from museum collections were photographed with a Canon Rebel T3i digital camera under cross-polarized light. Additionally, one of the specimens was documented with a Keyence BZ-9000 fluorescence microscope. The specimen was subsequently dissected to document all appendages in detail. UV light (377 nm) was used for illumination, consistent with the specimen’s autofluorescence capacities. For high-resolution images, composite imaging was applied.ResultsAll specimens differ in important aspects from all other known hippidan zoea larvae, and thus probably represent either previously unreported larvae or stages of known species, or larvae of unknown species. The sixth pleon segment articulates off the telson, a condition not previously reported in hippidan zoea larvae, but only for the next larva phase (megalopa). The larvae described here thus most likely represent the ultimate pelagic larval stages, or rare cases of ‘early megalopae’. The morphological features indicate that giant hippidan larvae perform defensive enrollment.ConclusionsOur investigation indicates a larger morphological diversity of hippidan larvae than was known previously. Moreover, their assumed functional morphology, similar to the condition in certain stomatopod larvae, indicates a not yet directly observable behavior by these larvae, namely defensive enrollment. In a wider context, we are only just beginning to understand the ecological roles of many crustacean larvae.Electronic supplementary materialThe online version of this article (doi:10.1186/s40851-016-0052-5) contains supplementary material, which is available to authorized users.

Spectral absorption of visual pigments in stomatopod larval photoreceptors.

Larval stomatopod eyes appear to be much simpler versions of adult compound eyes, lacking most of the visual pigment diversity and photoreceptor specializations. Our understanding of the visual pigment diversity of larval stomatopods, however, is based on four species, which severely limits our understanding of stomatopod eye ontogeny. To investigate several poorly understood aspects of stomatopod larval eye function, we tested two hypotheses surrounding the spectral absorption of larval visual pigments. First, we examined a broad range of species to determine if stomatopod larvae generally express a single, spectral class of photoreceptor. Using microspectrophotometry (MSP) on larvae captured in the field, we found data which further support this long-standing hypothesis. MSP was also used to test whether larval species from the same geographical region express visual pigments with similar absorption spectra. Interestingly, despite occupation of the same geographical location, we did not find evidence to support our second hypothesis. Rather, there was significant variation in visual pigment absorption spectra among sympatric species. These data are important to further our understanding of larval photoreceptor spectral diversity, which is beneficial to ongoing investigations into the ontogeny, physiology, and molecular evolution of stomatopod eyes.Electronic supplementary materialThe online version of this article (doi:10.1007/s00359-015-1063-y) contains supplementary material, which is available to authorized users.

Extreme morphologies of mantis shrimp larvae

Larvae of stomatopods (mantis shrimps) are generally categorized into four larval types: antizoea, pseudozoea (both representing early larval stages), alima and erichthus (the latter two representing later larval stages). These categories, however, do not reflect the existing morphological diversity of stomatopod larvae, which is largely unstudied. We describe here four previously unknown larval types with extreme morphologies. All specimens were found in the collections of the Zoological Museum, University of Copenhagen and were collected during the Danish Dana Expedition round the world 1928-30. These new larval types all represent erichthus-type larvae, especially differing in their shield morphologies. The shield morphology ranges from almost spherical to rather disc-like, with sometimes extremely elongated spines, but only a general systematic assignment of the larvae was possible. Further investigations of these larvae are crucial to understand their life habits and ecological impact, especially as stomatopod and other crustacean larvae might have a much more important position in the marine ecosystems than their corresponding adults.

Large-scale spatial variability of decapod and stomatopod larvae along the South Brazil Shelf

The spatial distribution of a spring/summer community of combined decapod and stomatopod larvae along the southwestern Atlantic shelf, and its possible linkages with hydrographical processes and with parental habitats were investigated. Vertical plankton hauls were performed between 21°S and 34°S, at 107 stations, distributed along 2000km of coastline and up to 400km offshore, during late spring 2010 and early summer 2011. Salinity and temperature were obtained with a CTD/rosette system, which provided seawater for chlorophyll and nutrient concentrations. A coupling between chlorophyll concentration and abundance of early larvae of benthic species was observed, suggesting that the larval release could be synchronized with phytoplankton maxima. Our findings indicated that the composition and abundance of larvae are strongly influenced by distance from the coast, freshwater sources and water mass distribution. Assemblages of larvae were observed in the most relevant environmental scenarios: (1) coastal environments, dominated by intertidal, shallow water or coastal species; (2) offshore environments, with predominance of holopelagic and deepwater species; and (3) southern continental runoff, mainly represented by benthic neritic crabs and shrimps. In addition, the large-scale distribution of larvae revealed a relationship with the adult’s distribution, shown mainly by the occurrence of larvae transported from the estuaries in the inner shelf and by larvae of the deepwater fauna found mainly along the outer shelf.

Hiding opaque eyes in transparent organisms: a potential role for larval eyeshine in stomatopod crustaceans.

Opaque screening pigments are a fundamental requisite for preserving resolution in image-forming eyes. Possession of any type of image-forming eye in a transparent, pelagic animal will thus undermine the ability of that animal to be invisible in the water column. Transparent, pelagic animals must therefore deal with the trade-off between the ability to see and the ability of other animals to see them. Stomatopod larvae, like many transparent crustaceans, possess specialized optics in their compound eyes that minimize the volume of the opaque retina. Though the volumes of these retinas are reduced, their opacity remains conspicuous to an observer. The light reflected from structures overlying the retinas of stomatopod crustacean larval eyes, referred to here as eyeshine, is hypothesized to further reduce the visibility of opaque retinas. Blue or green wavelengths of light are most strongly reflected in stomatopod larval eyeshine, suggesting a putative spectral matching to the light environment against which the larval eyes are viewed. We tested the efficacy of stomatopod crustacean larval eyeshine as an ocular camouflaging mechanism by photographing larvae in their natural light environment and analysing the contrast of eyes with the background light. To test for spectral matching between stomatopod larval eyeshine and the background light environment, we characterized the spectrum of eyeshine and calculated its performance using radiometric measurements collected at the time of each photographic series. These results are the first to demonstrate an operative mirror camouflage matched in both spectrum and radiance to the pelagic background light environment.

Aspects of larval distribution of Stomatopoda (Crustacea) in surface waters of the Colombian Pacific

The distribution of stomatopod larvae in surface waters of the Colombian Pacific was evaluated around September of the years 2001-2004. By means of a conical 363 μm-pore net 98 surface mesozooplankton samples were obtained, of which all stomatopod larvae were extracted. Their abundances were estimated to evaluate possible relationships, with temperature, salinity, catch time, moon phases, and surface circulation. Thermal (26.9°C) and saline (31.8 UPS) averages indicated normal conditions in the study area, with higher thermal influence on larval abundance, whose average was higher in 2004 (197 Ind./1000m3) than in the other periods (> 27 Ind./1000m3). Although larvae were found even 556 km offshore, in all periods the highest values (70-2282 Ind./1000 m3) occurred in south-central neritic waters (3-5°N), maybe related to the settlement of adult populations in that area. A trend in larval increasing by night, moon waning and moon waxing was observed. It is very likely that the hydrological dynamics of the study area has also an influence on larval distribution.

Defensive enrolment in mantis shrimp larvae (Malacostraca: Stomatopoda)

We describe a possible new defensive behaviour of larval stages of mantis shrimps (Stomatopoda). Mantis shrimp larvae are rarely observed in nature, thus the study is based on postures of museum material and functional morphological aspects. Specimens described here are tightly enrolled, their pleon is bent forward, and the telson is locked into the frontal margin of the shield. This margin has two lobes into which the two posterolateral spines of the telson fit. The shield shows further adaptions to enrolment; e.g., the ventral gape of the shield perfectly matches the width of the pleon and leaves no major gaps when the pleon is bent forward. Based on these observations, we briefly discuss the possibilities to infer behavioural aspects from functional morphological aspects. Enrolment in modern day organisms is primarily known from terrestrial arthropods, e.g., pill bugs and pill millipedes, but in the Palaeozoic it was mainly performed by marine organisms such as trilobites, agnostines and their relatives. Stomatopod larvae that appear to be able to perform enrolling in a marine environment are therefore a potential functional equivalent for better understanding the functional aspects of enrolment in extinct marine arthropods.

The Structure and Function of Stomatopod Larval Eyeshine

Event Abstract Back to Event The Structure and Function of Stomatopod Larval Eyeshine Kathryn D. Feller1* and Thomas W. Cronin1 1 University of Maryland Baltimore County, Biological Sciences, United States As a means of disguising themselves from visual predators in the pelagic environment, stomatopod larvae are almost entirely transparent. The only opaque structures on their body are the retinas, which lie at the center of a pair of fully functional compound eyes. Lying superficial to these retinas and deep to the elongated crystalline cones is a metallic blue or green reflecting pigment, which produces a strong eyeshine. Since this reflecting pigment does not lie in the optical pathway of a single photoreceptor, it is unlikely that its function is related to light sensitivity of the eye. Rather, eyeshine is hypothesized to reduce the contrast with the background pelagic light environment and thus function as an ocular camouflage. To test this hypothesis, larval eyes and their natural backgrounds were imaged underwater in their natural light environment from a series of controlled angles and orientations. Contrast between larval eyeshine reflectance and the background light environment was then both computed and directly measured from digital photographs using image analysis. The spectral reflectance of larval eyeshine was also measured in the lab using controlled angle white light illumination and a spectrometer. These data were then compared to environmental irradiance measurements collected from variable depths and times of day in the field. This is the first study to empirically test the function of larval eyeshine as an ocular camouflage. Keywords: Camouflage, Larvae, Stomatopod, Visual ecology Conference: Tenth International Congress of Neuroethology, College Park. Maryland USA, United States, 5 Aug - 10 Aug, 2012. Presentation Type: Poster (but consider for participant symposium and student poster award) Topic: Sensory: Vision Citation: Feller KD and Cronin TW (2012). The Structure and Function of Stomatopod Larval Eyeshine. Conference Abstract: Tenth International Congress of Neuroethology. doi: 10.3389/conf.fnbeh.2012.27.00152 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Apr 2012; Published Online: 07 Jul 2012. * Correspondence: Ms. Kathryn D Feller, University of Maryland Baltimore County, Biological Sciences, Baltimore, Maryland, United States, kfeller1@umbc.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Kathryn D Feller Thomas W Cronin Google Kathryn D Feller Thomas W Cronin Google Scholar Kathryn D Feller Thomas W Cronin PubMed Kathryn D Feller Thomas W Cronin Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Metabolism and chemical composition of phyllosoma larvae, with special reference to the tropical rock lobster Panulirus ornatus (Decapoda; Palinuridae)

Rates of oxygen consumption and ammonia excretion and chemical composition (water, ash and CN composition) were determined throughout larval development, from Stages I–IX, of Panulirus ornatus phyllosoma larvae raised in the laboratory. Dry mass (DM) specific oxygen consumption rates varied from 1.4 to 3.3 μl O 2 (DM) −1 h −1, showing a pattern of developmental decline. In contrast, specific ammonia excretion rates fluctuated irregularly from 0.02 to 0.067 μg NH 4–N (DM) −1 h −1, yielding oxygen consumption to ammonia excretion ratios (O:N atomic ratio) as wide as 51–180. With progressive development, ash decreased from 34% to 17% of DM while C composition increased from 33% to 41% of DM. No consistent changing pattern with development was seen for water contents (74–83% of WM), N composition (6.9–9.5% of DM) and C:N ratios (4.0–5.1). Supplemental data of both specific oxygen consumption and ammonia excretion rates of laboratory-raised Stage III P. homarus and wild Parribacus antarcticus phyllosoma (stage unknown) of this study and literature data on phyllosomas of other lobster species by previous workers were shown to be comparable to those of P. ornatus phyllosomas when the differences in DM and temperature were taken into account. No appreciable differences due to the origin of the specimens, whether wild or laboratory-raised, were evident. Comparison of the present results with those of stomatopod larvae and holoplanktonic crustaceans in the same tropical marine habitats revealed that phyllosoma larvae are characterized by somewhat lower DM specific oxygen consumption rates and N composition. The study revealed markedly reduced ammonia excretion rates in phyllosomas, suggesting reduced swimming activity and preferential utilization of dietary protein to somatic growth rather than metabolism.