Arhabdomeric cells in the retina of the median eyes of the scorpion

1978 ◽  
Vol 65 (4) ◽  
pp. 210-211 ◽  
Author(s):  
G. Fleissner ◽  
W. Siegler
Keyword(s):  
Arhabdomeric Cells ◽  
Median Eyes

THE QUALITY OF VISION IN THE CTENID SPIDER CUPIENNIUS SALEI

1992 ◽  
Vol 164 (1) ◽  
pp. 227-242 ◽  
Author(s):  
M. F. LAND ◽  
F. G. BARTH
Keyword(s):  
Predator Avoidance ◽  
Prey Capture ◽  
Cupiennius Salei ◽  
Quality Of Vision ◽  
Visual Behaviour ◽  
Similar Range ◽  
Retinal Resolution ◽  
Spider Cupiennius Salei ◽  
Median Eyes

Much is known about the mechanosensory behaviour of the spider Cupiennius Keyserling, but much less about its visual capabilities. In this study the quality of the optical image, the retinal resolution and the fields of view were assessed for each of the four pairs of eyes. The image is of good quality in all eyes. The principal (antero-median) eyes lack a tapetum and have an inter-receptor angle of 2.9°. The three secondary eyes (antero-lateral, postero-median and posterolateral) all have ‘gridiron’ tapeta with receptors arranged in rows. The angular separations (along rows × between rows) are 3.6° × 9.3°, 0.9° × 2.3° and 1.0° × 3.0°, respectively. Although the disposition of eyes on the head is similar to that of pisaurid spiders, all other features of the eyes, including the sizes and shapes of the fields of view, resemble those of lycosid spiders. The peripheral visual system of Cupiennius can thus, in principle, support a similar range of visual behaviour to that of lycosids, which includes prey capture, predator avoidance and courtship.

A new species of Tegenaria Latreille, 1804 (Araneae: Agelenidae) from western Iran

Zootaxa ◽  
2018 ◽  
Vol 4444 (1) ◽  
pp. 95
Author(s):  
ALIREZA ZAMANI ◽  
YURI M. MARUSIK ◽  
MOHAMMAD JAVAD MALEK-HOSSEINI
Keyword(s):  
New Species ◽  
Dorsal Side ◽  
Zagros Mountains ◽  
Northern Iran ◽  
Western Iran ◽  
Eastern Iran ◽  
The University ◽  
University Of Manchester ◽  
A New Species ◽  
Median Eyes

Agelenidae is a species rich and globally-distributed spider family comprising 1274 species in 77 genera (World Spider Catalog 2018). In Iran, this family is currently represented by eight species in four genera (Zamani et al. 2018). Being the second largest genus of the family (after Draconarius Ovtchinnikov, 1999), Tegenaria Latreille, 1804, currently encompasses 105 species that are primarily distributed in the Palaearctic (World Spider Catalog 2018; Marusik & Zamani 2015). So far, four species of this genus are known from Iran: Tegenaria domestica (Clerck, 1758) (western, northern, central and eastern Iran), T. lenkoranica (Guseinov et al., 2005) (northern Iran), T. pagana C.L. Koch, 1840 (northern Iran), and the endemic T. zamanii Marusik et Omelko, 2014 (northern Iran) (Zamani et al. 2018). Two of these species, T. lenkoranica and T. zamanii have been reported from caves (Malek-Hosseini & Zamani 2017). Considering the lack of studies on this genus in Iran, many species are undoubtedly awaiting to be discovered. During the biospeleological investigations of Zagros Mountains, a new species of Tegenaria was collected in western Iran, which is described and illustrated in this paper. The specimens were photographed using an Olympus Camedia E-520 camera attached to an Olympus SZX16 stereomicroscope and digital images were prepared using “CombineZP” image stacking software. Leg ratios were measured on the dorsal side and all measurements are given in millimeters. Measurements of leg are listed as: total length (femur, patella, tibia, metatarsus, tarsus). Standard abbreviations were used for the eyes: AME, anterior median eyes; ALE, anterior lateral eyes; PME, posterior median eyes; PLE, posterior lateral eyes. The specimens will be deposited in the Manchester Museum of the University of Manchester (MMUE). 

Comparative description of the Mediterranean erigonine spider Diplocephalus guidoi n. sp. (Araneae, Linyphiidae)

Zootaxa ◽  
2012 ◽  
Vol 3475 (1) ◽  
pp. 65 ◽  
Author(s):  
HOLGER FRICK ◽  
MARCO ISAIA
Keyword(s):  
Natural History ◽  
System Biology ◽  
Life Science ◽  
Dorsal Plate ◽  
Ventral Plate ◽  
History Museum ◽  
Radical Process ◽  
Private Collection ◽  
Comparative Description ◽  
Median Eyes

MCSNB: Museo Civico di Scienze Naturali “E. Caffi”, Bergamo, Italy; NMBE: Natural History Museum of Bern, Switzerland; HF: Private Collection Holger Frick; MI: Private Collection Marco Isaia, stored at Life Science and System Biology, University of Turin. ALE: anterior lateral eyes; AME: anterior median eyes; ARP: anterior radical process; DP: dorsal plate; DSA: distal suprategular apophysis; E: embolus; EM: embolic membrane; ISA: inner suprategular apophysis; PC: paracymbium; PLE: posterior lateral eyes; PME: posterior median eyes; RTP: radical tailpiece; ST: subtegulum; T: tegulum; TmI: Trichobothrium on metatarsus I; VP: ventral plate.

scholarly journals Repetitive spikes in photoreceptor axons of the scorpion eye. Invertebrate eye structure and tetrodotoxin.

1975 ◽  
Vol 66 (5) ◽  
pp. 649-655 ◽  
Author(s):  
C Belmonte ◽  
L J Stensaas
Keyword(s):  
Electron Microscopy ◽  
Optic Nerve ◽  
Light Intensity ◽  
Cell Membrane ◽  
Receptor Potential ◽  
Repetitive Firing ◽  
Normal Response ◽  
Nerve Impulses ◽  
Median Eyes

A graded depolarization accompanied by nerve impulses can be recorded from the scorpion lateral and median eyes in response to light. Electron microscopy shows that axons forming the optic nerve arise directly from the photoreceptors. Thus, photoreceptors must respond both by the generation of a slow receptor potential and the initiation of spikes. The latency of the first spike, and the maximal and mean discharge frequencies were a function of light intensity. Spikes were abolished by tetrodotoxin. Repetitive firing to light therefore appears to be a normal response of scorpion photoreceptors and is the result of regenerative Na influx in the cell membrane.

scholarly journals Spectral Sensitivities of the Anterior Median Eyes of the Orb Web Spiders, Argiope Bruennichii and A. Amoena

1978 ◽  
Vol 74 (1) ◽  
pp. 47-57
Author(s):  
SHIGEKI YAMASHITA ◽  
HIDEKI TATEDA
Keyword(s):  
Dark Adaptation ◽  
Circadian Oscillation ◽  
Visual Cells ◽  
Green Cell ◽  
Intracellular Receptor ◽  
Orb Web ◽  
Blue Cell ◽  
Orb Web Spiders ◽  
Median Eyes ◽  
Anterior Median

Spectral sensitivities of the anterior median eyes of the orb web spiders, Argiope bruennichii and A. amoena have been studied by recording extracellular ERGs and intracellular receptor potentials. The anterior median eyes have three types of visual cells, with maximum sensitivities at about 360 nm (u.v. cell), 480-500 nm (blue cell) and 540 nm (green cell). The blue cells are the most sensitive and have a circadian oscillation of sensitivity. The green cells show a hypersensitivity, i.e. the sensitivity is greater for about 90 s after the cessation of illumination than during dark adaptation. Respiration is necessary for the maintenance of hypersensitivity.

scholarly journals Myrmarachnine jumping spiders of the new subtribe Levieina from Papua New Guinea (Araneae, Salticidae, Myrmarachnini)

ZooKeys ◽  
2019 ◽  
Vol 842 ◽  
pp. 85-112 ◽  
Author(s):  
Wayne P. Maddison ◽  
Tamás Szűts
Keyword(s):  
Phylogenetic Analysis ◽  
New Species ◽  
Papua New Guinea ◽  
New Guinea ◽  
Coi Gene ◽  
New Genera ◽  
Jumping Spiders ◽  
Posterior Median ◽  
Three New Species ◽  
Median Eyes

A previously unreported radiation of myrmarachnine jumping spiders from New Guinea is described, which, although having few known species, is remarkably diverse in body forms. This clade is the new subtribe Levieina, represented by seven new species in three new genera. WithinLevieagen. n.are three new species,L.herbertisp. n.,L.lornaesp. n., andL.francesaesp. n., all of which are unusual among the myrmarachnines in appearing as typical salticids, not antlike.Papuamyrgen. n.superficially resemblesLigonipesKarsch, 1878 orRhombonotusL. Koch, 1879 as a compact antlike spider, but lacks their laterally-compressed palp and bears an ectal spur on the paturon of the chelicera. Two species ofPapuamyrgen. n.are described,Papuamyromhifosgasp. n.andP.pandorasp. n.Agorioidesgen. n., containingA.cherubinosp. n.andA.papagenasp. n., is antlike, with the carapace sunken inwards (concave) between the posterior lateral and posterior median eyes. Phylogenetic analysis of data from the 28S, 16SND1, and COI gene regions of 29 species of myrmarachnines shows that the three new genera form a clade that is sister to the subtribe Myrmarachnina (Myrmarachnesensu lato), with the subtribe Ligonipedina less closely related.

scholarly journals Neodrassex, a new genus of the Leptodrassex group (Araneae, Gnaphosidae) from South America

2012 ◽  
Vol 102 (3) ◽  
pp. 343-350 ◽  
Author(s):  
Ricardo Ott
Keyword(s):  
New Species ◽  
South America ◽  
New Genus ◽  
Rio Grande ◽  
Rio Grande Do Sul ◽  
Two New Species ◽  
Black Pigmentation ◽  
Median Eyes ◽  
Anterior Median

The new genus Neodrassex is proposed to include two new species of Gnaphosidae from Brazil. Neodrassex aureus sp. nov. is described from Amazonas, Paraná and Rio Grande do Sul states, and N. iguatemi sp. nov. is described from Paraná state. Neodrassex gen. nov. is characterized by small size, pale coloration, large anterior median eyes surrounded by black pigmentation, absence of a dorsal abdominal scutum in males and by the cheliceral dentition with 2-3 teeth on the promargin and 2-4 on the retromargin. The new genus is tentatively placed at the Leptodrassex group.

scholarly journals A harvestman (Arachnida: Opiliones) from the Early Devonian Rhynie cherts, Aberdeenshire, Scotland

2003 ◽  
Vol 94 (4) ◽  
pp. 341-354 ◽  
Author(s):  
Jason A. Dunlop ◽  
Lyall I. Anderson ◽  
Hans Kerp ◽  
Hagen Hass
Keyword(s):  
Reproductive Behaviour ◽  
Crown Group ◽  
Early Devonian ◽  
Morphological Stasis ◽  
Median Eyes

ABSTRACTA harvestman (Arachnida: Opiliones) is described from the Early Devonian (Pragian) Rhynie cherts, Aberdeenshire, Scotland. Eophalangium sheari gen. et sp. nov. is the oldest known harvestman. The material includes both males and a female preserving, respectively, a cuticle-lined penis and ovipositor within the opisthosoma. Both these structures are of essentially modern appearance. The Rhynie fossils also show tracheae which are, again, very similar to those of living harvestmen. This is the oldest unequivocal record of arachnid tracheal respiration and indicates that E. sheari was terrestrial. An annulate, setose ovipositor in the female suggests that it can be excluded from the clades Dyspnoi and Laniatores, in which the ovipositor lacks such annulations. However, the penis shows evidence of two muscles, a feature of uncertain polarity seen in modern Troguloidea (Dyspnoi). The presence of median eyes and long legs excludes Cyphophthalmi, and thus, E. sheari is tentatively referred to the suborder Eupnoi. Therefore, this remarkable material is implicitly a crown-group harvestman and is one of the oldest known crown-group chelicerates. It also suggests an extraordinary degree of morphological stasis within the eupnoid line, with the Devonian forms differing little in gross morphology – and perhaps in reproductive behaviour – from their modern counterp

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