scholarly journals Evolution of crab eye structures and the utility of ommatidia morphology in resolving phylogeny

2019 ◽  
Author(s):  
Javier Luque ◽  
W. Ted Allison ◽  
Heather D. Bracken-Grissom ◽  
Kelsey M. Jenkins ◽  
A. Richard Palmer ◽  
...  
Keyword(s):  
Visual Pigment ◽  
Fossil Record ◽  
Compound Eye ◽  
Compound Eyes ◽  
Decapod Crustaceans ◽  
Phylogenetic Studies ◽  
Visual Systems ◽  
Ideal Study ◽  
Males And Females ◽  
Visual Pigment Evolution

ABSTRACTImage-forming compound eyes are such a valuable adaptation that similar visual systems have evolved independently across crustaceans. But if different compound eye types have evolved independently multiple times, how useful are eye structures and ommatidia morphology for resolving phylogenetic relationships? Crabs are ideal study organisms to explore these questions because they have a good fossil record extending back into the Jurassic, they possess a great variety of optical designs, and details of eye form can be compared between extant and fossil groups. True crabs, or Brachyura, have been traditionally divided into two groups based on the position of the sexual openings in males and females: the so-called ‘Podotremata’ (females bearing their sexual openings on the legs), and the Eubrachyura, or ‘higher’ true crabs (females bearing their sexual openings on the thorax). Although Eubrachyura appears to be monophyletic, the monophyly of podotreme crabs remains controversial and therefore requires exploration of new character systems. The earliest podotremous lineages share the plesiomorphic condition of ‘mirror’ reflecting superposition eyes with most shrimp, lobsters, and anomurans (false crabs and allies). The optical mechanisms of fossil and extant podotreme groups more closely related to Eubrachyura, however, are still poorly investigated. To better judge the phylogenetic utility of compound eye form, we investigated the distribution of eye types in fossil and extant podotreme crabs. Our findings suggest the plesiomorphic ‘mirror’ eyes—seen in most decapod crustaceans including the earliest true crabs—has been lost in several ‘higher’ podotremes and in eubrachyurans. We conclude that the secondary retention of larval apposition eyes has existed in eubrachyurans and some podotremes since at least the Early Cretaceous, and that the distribution of eye types among true crabs supports a paraphyletic podotreme grade, as suggested by recent molecular and morphological phylogenetic studies. We also review photoreceptor structure and visual pigment evolution, currently known in crabs exclusively from eubrachyuran representatives. These topics are critical for future expansion of research on podotremes to deeply investigate the homology of eye types across crabs.

How small can small be: The compound eye of the parasitoid waspTrichogramma evanescens(Westwood, 1833) (Hymenoptera, Hexapoda), an insect of 0.3- to 0.4-mm total body size

2010 ◽  
Vol 28 (4) ◽  
pp. 295-308 ◽  
Author(s):  
STEFAN FISCHER ◽  
CARSTEN H.G. MÜLLER ◽  
V. BENNO MEYER-ROCHOW
Keyword(s):  
Compound Eye ◽  
Uv Light ◽  
Parasitoid Wasp ◽  
Pigment Cells ◽  
Compound Eyes ◽  
Trichogramma Evanescens ◽  
Cone Cells ◽  
Males And Females ◽  
Total Body ◽  
Effective Use

AbstractWith a body length of only 0.3–0.4 mm, the parasitoid waspTrichogramma evanescens(Westwood) is one of the smallest insects known. Yet, despite its diminutive size, it possesses compound eyes that are of oval shapes, measuring across their long axes in dorsoventral direction 63.39 and 71.11μm in males and females, respectively. The corresponding facet diameters are 5.90μm for males and 6.39μm for females. Owing to the small radii of curvature of the eyes in males (34.59μm) and females (42.82μm), individual ommatidia are short with respective lengths of 24.29 and 34.97μm. The eyes are of the apposition kind, and each ommatidium possesses four cone cells of the eucone type and a centrally fused rhabdom, which throughout its length is formed by no more than eight retinula cells. A ninth cell occupies the place of the eighth retinula cell in the distal third of the rhabdom. The cone is shielded by two primary and six secondary pigment cells, all with no apparent extensions to the basement membrane, unlike the case in larger hymenopterans. The regular and dense packing of the rhabdoms reflects an effective use of space. Calculations on the optics of the eyes ofTrichogrammasuggest that the eyes need not be diffraction limited, provided they use mostly shorter wavelengths, that is, UV light. Publications on the visual behavior of these wasps confirmTrichogramma’s sensitivity to UV radiation. On the basis of our findings, some general functional conclusions for very small compound eyes are formulated.

scholarly journals Spectral tuning and the visual ecology of mantis shrimps

2000 ◽  
Vol 355 (1401) ◽  
pp. 1263-1267 ◽  
Author(s):  
Thomas W. Cronin ◽  
N. Justin Marshall ◽  
Roy L. Caldwell
Keyword(s):  
Motion Detection ◽  
Visual Pigment ◽  
Spatial Vision ◽  
Compound Eyes ◽  
Polarization Vision ◽  
Spectral Tuning ◽  
Maximum Coverage ◽  
Visual Systems ◽  
Visual Tasks

The compound eyes of mantis shrimps (stomatopod crustaceans) include an unparalleled diversity of visual pigments and spectral receptor classes in retinas of each species. We compared the visual pigment and spectral receptor classes of 12 species of gonodactyloid stomatopods from a variety of photic environments, from intertidal to deep water (> 50 m), to learn how spectral tuning in the different photoreceptor types is modified within different photic environments. Results show that receptors of the peripheral photoreceptors, those outside the midband which are responsible for standard visual tasks such as spatial vision and motion detection, reveal the well–known pattern of decreasing λ max with increasing depth. Receptors of midband rows 5 and 6, which are specialized for polarization vision, are similar in all species, having visual λ max –values near 500 nm, independent of depth. Finally, the spectral receptors of midband rows 1 to 4 are tuned for maximum coverage of the spectrum of irradiance available in the habitat of each species. The quality of the visual worlds experienced by each species we studied must vary considerably, but all appear to exploit the full capabilities offered by their complex visual systems.

scholarly journals Structure and function of a compound eye, more than half a billion years old

2017 ◽  
Vol 114 (51) ◽  
pp. 13489-13494 ◽  
Author(s):  
Brigitte Schoenemann ◽  
Helje Pärnaste ◽  
Euan N. K. Clarkson
Keyword(s):  
Fossil Record ◽  
Lower Cambrian ◽  
Compound Eye ◽  
Cellular Level ◽  
Structure And Function ◽  
Cellular Systems ◽  
Compound Eyes ◽  
Internal Structures ◽  
The Baltic ◽  
And Function

Until now, the fossil record has not been capable of revealing any details of the mechanisms of complex vision at the beginning of metazoan evolution. Here, we describe functional units, at a cellular level, of a compound eye from the base of the Cambrian, more than half a billion years old. Remains of early Cambrian arthropods showed the external lattices of enormous compound eyes, but not the internal structures or anything about how those compound eyes may have functioned. In a phosphatized trilobite eye from the lower Cambrian of the Baltic, we found lithified remnants of cellular systems, typical of a modern focal apposition eye, similar to those of a bee or dragonfly. This shows that sophisticated eyes already existed at the beginning of the fossil record of higher organisms, while the differences between the ancient system and the internal structures of a modern apposition compound eye open important insights into the evolution of vision.

scholarly journals Evolution of Eye Reduction and Loss in Trilobites and Some Related Fossil Arthropods

2018 ◽  
Vol 2 (5) ◽  
pp. 272 ◽  
Author(s):  
Brigitte Schoenemann
Keyword(s):  
Fossil Record ◽  
Compound Eye ◽  
Compound Eyes ◽  
Early Suggestion ◽  
Time Period ◽  
Highly Sensitive ◽  
Lens Diameter ◽  
Dim Light ◽  
Vast Area

The fossil record of arthropod compound eyes reflects different modes and occasions of eye reduction and blindness. In the best-studied fossil examples, the trilobites [trilobites: extinct arthropods, dominant during the Palaeozoic], which have an excellent geological record, eyes are primary structures, and in all known genera which lack them, eye-loss is always secondary. Once the eyes were lost, they never were never re-established. The most striking examples occur in the Upper Devonian, when two unrelated major groups of trilobites, with different kinds of eyes, underwent eye reduction and even total loss of the eyes over the same time period, undoubtedly due to long-term environmental change. One reason is that a mud blanket spread over a vast area, there was no firm substrate, and many trilobites became small and many became endobenthic, reducing or losing their eyes in the process. Toxic environmental conditions may also have had an effect. Certain coeval forms remained, however, which still possess perfectly good compound eyes. Either they found vacant refuges where they could survive, or alternatively their visual systems were elaborate enough to adapt to the changing conditions. Another inducement for evolving small, reduced compound eyes is to become a tiny organism oneself, with simply not enough space to establish a regular and functional compound eye, and in such minaturised eyes special adaptations for capturing enough photons are necessary. Thus very small compound eyes often establish wide acceptance angles of their ommatidia, collecting light over large angular ranges of space and it is beneficial to have a wide rhabdom provided that it is short, has a wide lens diameter, and perhaps even possess highly sensitive receptor cells. We find such a miniaturised system in the first recorded planktonic trilobite. Another kind of reduction of a compound eye, or parts of it, also occurs, if selective pressure claims for a high specialisation of eyes that results in several facets fusing into a single functional unit. This probably can be found in phacopid trilobites, ~400 million years old. Here the enlarged aperture of a resulting large lens may allow vision under dim light conditions such as at greater depth. The fossil record gives relatively little evidence about parasites, which often have reduced eyes. Agnostida are blind relatives of trilobites which lived during the Cambrian and Ordovician. An early suggestion was that some of these were parasitic, but this was never commonly adopted. Finally penstastomids (Crustacea), worm-like parasitic organisms, already have been blind from the Cambrian (~487Ma).

Spreading of hemiretinal projections in the ipsilateral tectum following unilateral enucleation: a study of optic nerve regeneration in Xenopus with one compound eye

Development ◽  
1981 ◽  
Vol 61 (1) ◽  
pp. 259-276
Author(s):  
Charles Straznicky ◽  
David Tay
Keyword(s):  
Optic Nerve ◽  
Nerve Regeneration ◽  
Compound Eye ◽  
Rapid Expansion ◽  
Compound Eyes ◽  
Optic Nerve Regeneration ◽  
Xenopus Embryos ◽  
Retinotectal Projections ◽  
Optic Fibre

Right compound eyes were formed in Xenopus embryos at stages 32–33 by the fusion of two nasal (NN), two ventral (VV) or two temporal (TT) halves. Shortly after metamorphosis the optic nerve from the compound eye was sectioned and the left intact eye removed. The retinotectal projections from the compound eye to the contralateral and ipsilateral tecta were studied by [3H]proline autoradiography and electrophysiological mapping between 6 weeks and 5 months after the postmetamorphic surgery. The results showed that NN and VV eyes projected to the entire extent of both tecta. In contrast, optic fibre projection from TT eyes, although more extensive than the normal temporal hemiretinal projection, failed to cover the caudomedial portion of the tecta. The visuotectal projections in all three combinations corresponded to typical reduplicated maps to be expected from such compound eyes, where each of the hemiretinae projected across the contralateral and ipsilateral tecta in an overlapping fashion. The rapid expansion of the hemiretinal projections of the compound eyes in the ipsilateral tectum following the removal of the resident optic fibre projection suggests that tectal markers may be carried and deployed by the incoming optic fibres themselves.

scholarly journals Two visual pigment opsins, one expressed in the dorsal region and another in the dorsal and the ventral regions, of the compound eye of a dragonfly,Sympetrum frequens

1996 ◽  
Vol 2 (3) ◽  
pp. 209-209 ◽  
Author(s):  
Kentaro Arikawa ◽  
Koichi Ozaki ◽  
Takanari Tsuda ◽  
Junko Kitamoto ◽  
Yuji Mishina
Keyword(s):  
Visual Pigment ◽  
Compound Eye ◽  
Dorsal Region ◽  
Sympetrum Frequens

scholarly journals Differences in orthodenticle expression promote ommatidial size variation between Drosophila species

2021 ◽  
Author(s):  
Montserrat Torres-Oliva ◽  
Elisa Buchberger ◽  
Alexandra D. Buffry ◽  
Maike Kittelmann ◽  
Lauren Sumner-Rooney ◽  
...  
Keyword(s):  
Natural Variation ◽  
Gene Expression Analysis ◽  
Compound Eye ◽  
Chromosomal Region ◽  
Size Variation ◽  
Compound Eyes ◽  
Positional Candidate ◽  
Eye Size ◽  
Drosophila Mauritiana ◽  
Differential Timing

The compound eyes of insects exhibit extensive variation in ommatidia number and size, which affects how they see and underlies adaptations in their vision to different environments and lifestyles. However, very little is known about the genetic and developmental bases underlying differences in compound eye size. We previously showed that the larger eyes of Drosophila mauritiana compared to D. simulans is caused by differences in ommatidia size rather than number. Furthermore, we identified an X-linked chromosomal region in D. mauritiana that results in larger eyes when introgressed into D. simulans. Here, we used a combination of fine-scale mapping and gene expression analysis to further investigate positional candidate genes on the X chromosome. We found that orthodenticle is expressed earlier in D. mauritiana than in D. simulans during ommatidial maturation in third instar larvae, and we further show that this gene is required for the correct organisation and size of ommatidia in D. melanogaster. Using ATAC-seq, we have identified several candidate eye enhancers of otd as well as potential direct targets of this transcription factor that are differentially expressed between D. mauritiana and D. simulans. Taken together, our results suggest that differential timing of otd expression contributes to natural variation in ommatidia size between D. mauritiana and D. simulans, which provides new insights into the mechanisms underlying the regulation and evolution of compound eye size in insects.

scholarly journals Digging deeper: new gene order rearrangements and distinct patterns of codons usage in mitochondrial genomes among shrimps from the Axiidea, Gebiidea and Caridea (Crustacea: Decapoda)

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e2982 ◽  
Author(s):  
Mun Hua Tan ◽  
Han Ming Gan ◽  
Yin Peng Lee ◽  
Gary C.B. Poore ◽  
Christopher M. Austin
Keyword(s):  
Codon Usage ◽  
Gene Order ◽  
Phylogenetic Relationships ◽  
Decapod Crustacean ◽  
Illumina Miseq ◽  
Comparative Genomic ◽  
Decapod Crustaceans ◽  
Phylogenetic Studies ◽  
Significant Gene ◽  
Taxonomic Groups

BackgroundWhole mitochondrial DNA is being increasingly utilized for comparative genomic and phylogenetic studies at deep and shallow evolutionary levels for a range of taxonomic groups. Although mitogenome sequences are deposited at an increasing rate into public databases, their taxonomic representation is unequal across major taxonomic groups. In the case of decapod crustaceans, several infraorders, including Axiidea (ghost shrimps, sponge shrimps, and mud lobsters) and Caridea (true shrimps) are still under-represented, limiting comprehensive phylogenetic studies that utilize mitogenomic information.MethodsSequence reads from partial genome scans were generated using the Illumina MiSeq platform and mitogenome sequences were assembled from these low coverage reads. In addition to examining phylogenetic relationships within the three infraorders, Axiidea, Gebiidea, and Caridea, we also investigated the diversity and frequency of codon usage bias and mitogenome gene order rearrangements.ResultsWe present new mitogenome sequences for five shrimp species from Australia that includes two ghost shrimps,Callianassa ceramicaandTrypaea australiensis, along with three caridean shrimps,Macrobrachium bullatum,Alpheus lobidens, andCaridinacf.nilotica. Strong differences in codon usage were discovered among the three infraorders and significant gene order rearrangements were observed. While the gene order rearrangements are congruent with the inferred phylogenetic relationships and consistent with taxonomic classification, they are unevenly distributed within and among the three infraorders.DiscussionOur findings suggest potential for mitogenome rearrangements to be useful phylogenetic markers for decapod crustaceans and at the same time raise important questions concerning the drivers of mitogenome evolution in different decapod crustacean lineages.

The development of the retinotectal projection in Xenopus with one compound eye

Development ◽  
1975 ◽  
Vol 33 (3) ◽  
pp. 775-787
Author(s):  
Joan D. Feldman ◽  
R. M. Gaze
Keyword(s):  
Compound Eye ◽  
Contralateral Side ◽  
Compound Eyes ◽  
Stages Of Development ◽  
Ipsilateral Side ◽  
Retinotectal Projection ◽  
Xenopus Embryos ◽  
Donor Embryo

Double-nasal and double-temporal compound eyes were constructed in Xenopus embryos at stages 32 and 37/38. A particular half was removed from the host eye anlage and replaced with the opposite half-eye from the contralateral side of a donor embryo. Control operations consisted of removing a half-eye and replacing it with a similar half from the ipsilateral side of the donor embryo. Whereas in control animals, each half-eye projected its fibres to the appropriate half-tectum, in operated animals each half of the compound eye spread its optic teiminals across the entire rostrocaudal extent of the dorsal tectal surface. The area of tectal surface covered by ganglion fibre terminals was similar in operated animals mapped at successive stages of development to that previously observed in normal animals at equivalent stages. Therefore the factors responsible for the extended distribution of fibre terminals from each half of a compound eye must exist at least from mid-tadpole life, and thereafter be continuously present throughout development.

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