Book-lungs in a Lower Carboniferous scorpion

Jeram, Andrew J.

doi:10.1038/343360a0

Cited by 30 publications

(23 citation statements)

References 5 publications

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“…No such structure is known in the present-day Crustacea, in which gills usually developed in a direct connection with appendages (Boxshall, 2004). The similarity to chelicerate book lungs, suggested by Gall and Grauvogel (1967), appears remote at best, based on the evidence now available on the Triassic Halicynelike cycloids, and apparently has resulted from their similar function (see Jeram, 1990;Reisinger et al, 1991).…”

Section: Evolutionary Relationships Of the Cycloidsmentioning

confidence: 88%

Gill structure and relationships of the Triassic cycloid crustaceans

Dzik

2008

Journal of Morphology

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Unusually well-preserved fossils of a Halicyne-like cycloid crustacean frequently occur in the early Late Triassic lacustrine clay bed at Krasiejów in Opole Silesia, southern Poland. Its gill-like structures form a horseshoe-shaped pair of units composed of numerous calcified blades with reverse U-shaped cross-section. Originally, these were parallel slits opening on the ventral surface of the carapace. Lobation of the posterior margin of the carapace, of unusually large mature size for the group, make the animal different from other members of Halicynidae, and the new name Opolanka decorosa gen. et sp. nov. is proposed for it. More completely preserved specimens of cycloids from Vosges, France, and Madagascar show that the slit openings were located above radially arranged coxae of the walking appendages and a reduced abdomen. The disposition and arrangement of the cycloid gills suggest at least close analogy, and possibly homology, with the "respiratory areas" of the Branchiura, serving mostly as ion-exchange organs. It is proposed that they originated, in connection with the body size increase and adaptation to fresh-water environment, as radially arranged infoldings of the respiratory areas cuticle, with strongly calcified rigid dorsal parts suspended from the carapace. At least three ecologically and anatomically distinct lineages were represented in the order Cyclida, which was probably initially confined to marine environments and gradually adapted to life in continental waters. New taxa Schraminidae fam. nov. (with Schramine gen. nov.) and Americlidae fam. nov. (with Americlus gen. nov.) are proposed.

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Section: Evolutionary Relationships Of the Cycloidsmentioning

confidence: 88%

Gill structure and relationships of the Triassic cycloid crustaceans

Dzik

2008

Journal of Morphology

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“…Gills above the posterior margin of mesosomal plates or sternites were hypothesized for Paleozoic aquatic scorpions (Kjellesvig-Waering, 1986), but evidence for such gills is lacking. Fossil indications of book lungs at this site have been reported (Jeram, 1990(Jeram, , 2001.…”

Section: Book Lung Evolutionmentioning

confidence: 93%

“…3B) have small knobs more densely distributed than elsewhere on the body, and they have a rounded structure in contrast to more pointed cuticular knobs at other sites. Above the posterior sternite margin, there was never an indication of book lung lamellae or prominent gill-like structures as hypothesized for some fossil scorpions (Jeram, 1990(Jeram, , 2001Kjellesvig-Waering, 1986). The initial oval slits near the sternite margin (Figs.…”

Section: Embryo Stage When Spiracles Appearmentioning

confidence: 95%

“…Book lungs and spiracles that may lead to book lungs are commonly considered as key indicators of terrestrialization among fossil and recent arachnids (Vogel and Durden, 1966;Kjellesvig-Waering, 1986;Jeram, 1990Jeram, , 2001Dunlop, 1998;Dunlop and Webster, 1999). More recent studies in xiphosuran, scorpion, and spider embryos have shown similar patterns of gene expression at the bilateral opisthosomal sites where gills or book lungs eventually form (Popadić et al, 1998;Popadić and Nagy, 2001;Damen et al, 2002;Simonnet et al, 2004Simonnet et al, , 2006.…”

Section: Abstract: Scorpiones;mentioning

confidence: 98%

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Development of respiratory structures in embryos and first and second instars of the bark scorpion, Centruroides gracilis (Scorpiones: Buthidae)

Farley

2008

Journal of Morphology

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The SEM was used to study the development of respiratory structures in successive stages in relation to the overall changes occurring in the scorpions. Book lung development is a slow process, starting with spiracles and a sac-like atrium in the early embryo and continuing lamellar formation to 150 or more in the adult. In the embryo, the primordial epithelial cells become aligned in a planar pattern as they secrete granules of material that aggregate spontaneously to form the cuticular walls of the lamellae. A blade-like structure is formed consisting of cells sandwiched within the two cuticle walls they secreted. These cells are in the primordial air channel. The adjacent hemolymph channel is nearly devoid of cells, but cross-bridges develop and help stabilize the cuticle walls and maintain the width of the channel. The cells in the primordial air channel undergo cytolysis, leaving it open for air except for cuticular cross-bridges. Development continues in the newborn (first instars); the air channels of some lamellae still contain cells and are not yet functional for gas exchange. The first instars are weak and relatively inactive. They climb up on the mother's dorsum until the first molt (about 8 days). With the cuticular walls of the lamellae in place, cells adhering to the wall in the hemolymph channel produce a thin, new tissue layer (epithelium) on the lamellar wall facing the hemolymph channel. This layer has many discontinuities as though it is slowly developing. Formation of the tissue layer and cytolysis of the cells in the air channels continue through the first molt in which little book lung cuticle is shed as exuvium. The air channels of the second instars (foraging nymphs) are now cell free and open for air passage except for the cross-bridges. The tissue layer is still incomplete and continues to be formed. It may provide the hypodermal primordium for cuticle replacement in later molts, but development was not studied beyond the second instar except for comparison with book lungs in the adult. The blade-like lamellae in the adult are larger and more numerous than in the second instar, but in the anterior book lung the shape of the cuticle wall and cross-bridges and the widths of the air and hemolymph channels are about the same as in the second instar. The air channels in the posterior part of the lamellae have distinctive, vein-like space-holders. The similarity of the adult anterior lamellae with those in the second instar suggests retention of this part through the 4-5 molts to maturation, and/or cell processes like those in the embryo are repeated, but this needs to be examined in further studies of cell and cuticle changes before and during the molts.

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“…However, the sister group relationships of scorpions and eurypterids are not clearly resolved (Dunlop and Braddy 2001;Giribet et al 2002) and the similarities between them might as well be plesiomorphic (Weygoldt 1998). The first scorpions with preserved respiratory organs reveal clear book lungs indicating a terrestrial mode of life (Selden and Jeram 1989;Jeram 1990Jeram , 2001. The so-called gills of Waeringoscorpio hefteri Størmer, 1970(see Størmer 1970 are equivocal as respiratory organs and do not resemble the gills of xiphosurans (see also Dunlop and Webster 1999).…”

Section: How Convincing Are the Arguments For Book Lung Convergence?mentioning

confidence: 94%