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The embryonic development of the central American wandering spider Cupiennius salei.

Wolff C, Hilbrant M - Front. Zool. (2011)

Bottom Line: The imaging procedure also elucidates the encircling border between the cell-dense embryo hemisphere and the hemisphere with much lower cell density (a structure termed 'equator' in earlier studies).Our improved staging system of development in C. salei development should be of considerable value to future comparative studies of animal development.A dense germ disc is not evident during development in C. salei, but we show that the gastrulation process is similar to that in spider species that do have a dense germ disc.

View Article: PubMed Central - HTML - PubMed

Affiliation: Humboldt-Universität zu Berlin Institut für Biologie/Vergleichende Zoologie Philippstraße 13, 10115 Berlin, Germany. carsten.wolff@rz.hu-berlin.de.

ABSTRACT

Background: The spider Cupiennius salei (Keyserling 1877) has become an important study organism in evolutionary and developmental biology. However, the available staging system for its embryonic development is difficult to apply to modern studies, with strong bias towards the earliest developmental stages. Furthermore, important embryonic events are poorly understood. We address these problems, providing a new description of the embryonic development of C. salei. The paper also discusses various observations that will improve our understanding of spider development.

Results: Conspicuous developmental events were used to define numbered stages 1 to 21. Stages 1 to 9 follow the existing staging system for the spider Achaearanea tepidariorum, and stages 10 to 21 provide a high-resolution description of later development. Live-embryo imaging shows cell movements during the earliest formation of embryonic tissue in C. salei. The imaging procedure also elucidates the encircling border between the cell-dense embryo hemisphere and the hemisphere with much lower cell density (a structure termed 'equator' in earlier studies). This border results from subsurface migration of primordial mesendodermal cells from their invagination site at the blastopore. Furthermore, our detailed successive sequence shows: 1) early differentiation of the precheliceral neuroectoderm; 2) the morphogenetic process of inversion and 3) initial invaginations of the opisthosomal epithelium for the respiratory system.

Conclusions: Our improved staging system of development in C. salei development should be of considerable value to future comparative studies of animal development. A dense germ disc is not evident during development in C. salei, but we show that the gastrulation process is similar to that in spider species that do have a dense germ disc. In the opisthosoma, the order of appearance of precursor epithelial invaginations provides evidence for the non-homology of the tracheal and book lung respiratory systems.

No MeSH data available.


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First and Second instar of C. salei. All scale bars 500 μm. SEMs, a-b, g-h; light micrographs, c-f. a-e First instar. a: Ventral view. Numbers indicate the seven podomeres of L2. White arrows indicate the slit-like opening of the book lung system. a': Detail of the tip of the left chelicere showing the fang (f), a sharp cuticular claw on which the opening of the poison gland is visible (white arrow head). Black arrows indicate the retromarginal teeth at the base of the chelicere. a'': Detail of the mouth region. Numbers indicate the six podomeres of the pedipalp. b: Dorsal view. c-e: Dorsal view of increasingly older first instars, illustrating the increase in pigmentation. f-h Second instar. f: Dorsal view. g: SEM image. Dorsal view shows the arrangement of the eyes (al: anterior lateral eye, am: anterior median eye, pl: posterior lateral eye, pm: posterior median eye) and the petiolus (white arrow). g' Frontal view. Higher magnification of the eye region of g. h: Ventral view. The mouth opening is surrounded antero-laterally by the two cheliceres (Ch), laterally by the endites (en) of the pedipalps (P) and posteriorly by the labium (Lab). The labrum anterior to the mouth opening is covered by the cheliceres. L1-L4, walking leg one to four; Lb, labrum; Pet: petiolus; PS, prosomal shield; Sp, spinnerets; St, sternum.
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Figure 19: First and Second instar of C. salei. All scale bars 500 μm. SEMs, a-b, g-h; light micrographs, c-f. a-e First instar. a: Ventral view. Numbers indicate the seven podomeres of L2. White arrows indicate the slit-like opening of the book lung system. a': Detail of the tip of the left chelicere showing the fang (f), a sharp cuticular claw on which the opening of the poison gland is visible (white arrow head). Black arrows indicate the retromarginal teeth at the base of the chelicere. a'': Detail of the mouth region. Numbers indicate the six podomeres of the pedipalp. b: Dorsal view. c-e: Dorsal view of increasingly older first instars, illustrating the increase in pigmentation. f-h Second instar. f: Dorsal view. g: SEM image. Dorsal view shows the arrangement of the eyes (al: anterior lateral eye, am: anterior median eye, pl: posterior lateral eye, pm: posterior median eye) and the petiolus (white arrow). g' Frontal view. Higher magnification of the eye region of g. h: Ventral view. The mouth opening is surrounded antero-laterally by the two cheliceres (Ch), laterally by the endites (en) of the pedipalps (P) and posteriorly by the labium (Lab). The labrum anterior to the mouth opening is covered by the cheliceres. L1-L4, walking leg one to four; Lb, labrum; Pet: petiolus; PS, prosomal shield; Sp, spinnerets; St, sternum.

Mentions: The first instar emerges from the postembryo after about 3 days (at 25 C). Contrary to earlier observations [48] we never witnessed a first instar hatching directly from the egg. The walking legs of the first instar extend laterally (Figures 19b, c-e). The cheliceres have two so-called retromarginal teeth on their bases (black arrows; Figure 19a'). Both teeth are positioned opposite the folded fangs. Distal-laterally, the fangs bear an opening to the poison gland (white arrow head; Figure 19a').


The embryonic development of the central American wandering spider Cupiennius salei.

Wolff C, Hilbrant M - Front. Zool. (2011)

First and Second instar of C. salei. All scale bars 500 μm. SEMs, a-b, g-h; light micrographs, c-f. a-e First instar. a: Ventral view. Numbers indicate the seven podomeres of L2. White arrows indicate the slit-like opening of the book lung system. a': Detail of the tip of the left chelicere showing the fang (f), a sharp cuticular claw on which the opening of the poison gland is visible (white arrow head). Black arrows indicate the retromarginal teeth at the base of the chelicere. a'': Detail of the mouth region. Numbers indicate the six podomeres of the pedipalp. b: Dorsal view. c-e: Dorsal view of increasingly older first instars, illustrating the increase in pigmentation. f-h Second instar. f: Dorsal view. g: SEM image. Dorsal view shows the arrangement of the eyes (al: anterior lateral eye, am: anterior median eye, pl: posterior lateral eye, pm: posterior median eye) and the petiolus (white arrow). g' Frontal view. Higher magnification of the eye region of g. h: Ventral view. The mouth opening is surrounded antero-laterally by the two cheliceres (Ch), laterally by the endites (en) of the pedipalps (P) and posteriorly by the labium (Lab). The labrum anterior to the mouth opening is covered by the cheliceres. L1-L4, walking leg one to four; Lb, labrum; Pet: petiolus; PS, prosomal shield; Sp, spinnerets; St, sternum.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Figure 19: First and Second instar of C. salei. All scale bars 500 μm. SEMs, a-b, g-h; light micrographs, c-f. a-e First instar. a: Ventral view. Numbers indicate the seven podomeres of L2. White arrows indicate the slit-like opening of the book lung system. a': Detail of the tip of the left chelicere showing the fang (f), a sharp cuticular claw on which the opening of the poison gland is visible (white arrow head). Black arrows indicate the retromarginal teeth at the base of the chelicere. a'': Detail of the mouth region. Numbers indicate the six podomeres of the pedipalp. b: Dorsal view. c-e: Dorsal view of increasingly older first instars, illustrating the increase in pigmentation. f-h Second instar. f: Dorsal view. g: SEM image. Dorsal view shows the arrangement of the eyes (al: anterior lateral eye, am: anterior median eye, pl: posterior lateral eye, pm: posterior median eye) and the petiolus (white arrow). g' Frontal view. Higher magnification of the eye region of g. h: Ventral view. The mouth opening is surrounded antero-laterally by the two cheliceres (Ch), laterally by the endites (en) of the pedipalps (P) and posteriorly by the labium (Lab). The labrum anterior to the mouth opening is covered by the cheliceres. L1-L4, walking leg one to four; Lb, labrum; Pet: petiolus; PS, prosomal shield; Sp, spinnerets; St, sternum.
Mentions: The first instar emerges from the postembryo after about 3 days (at 25 C). Contrary to earlier observations [48] we never witnessed a first instar hatching directly from the egg. The walking legs of the first instar extend laterally (Figures 19b, c-e). The cheliceres have two so-called retromarginal teeth on their bases (black arrows; Figure 19a'). Both teeth are positioned opposite the folded fangs. Distal-laterally, the fangs bear an opening to the poison gland (white arrow head; Figure 19a').

Bottom Line: The imaging procedure also elucidates the encircling border between the cell-dense embryo hemisphere and the hemisphere with much lower cell density (a structure termed 'equator' in earlier studies).Our improved staging system of development in C. salei development should be of considerable value to future comparative studies of animal development.A dense germ disc is not evident during development in C. salei, but we show that the gastrulation process is similar to that in spider species that do have a dense germ disc.

View Article: PubMed Central - HTML - PubMed

Affiliation: Humboldt-Universität zu Berlin Institut für Biologie/Vergleichende Zoologie Philippstraße 13, 10115 Berlin, Germany. carsten.wolff@rz.hu-berlin.de.

ABSTRACT

Background: The spider Cupiennius salei (Keyserling 1877) has become an important study organism in evolutionary and developmental biology. However, the available staging system for its embryonic development is difficult to apply to modern studies, with strong bias towards the earliest developmental stages. Furthermore, important embryonic events are poorly understood. We address these problems, providing a new description of the embryonic development of C. salei. The paper also discusses various observations that will improve our understanding of spider development.

Results: Conspicuous developmental events were used to define numbered stages 1 to 21. Stages 1 to 9 follow the existing staging system for the spider Achaearanea tepidariorum, and stages 10 to 21 provide a high-resolution description of later development. Live-embryo imaging shows cell movements during the earliest formation of embryonic tissue in C. salei. The imaging procedure also elucidates the encircling border between the cell-dense embryo hemisphere and the hemisphere with much lower cell density (a structure termed 'equator' in earlier studies). This border results from subsurface migration of primordial mesendodermal cells from their invagination site at the blastopore. Furthermore, our detailed successive sequence shows: 1) early differentiation of the precheliceral neuroectoderm; 2) the morphogenetic process of inversion and 3) initial invaginations of the opisthosomal epithelium for the respiratory system.

Conclusions: Our improved staging system of development in C. salei development should be of considerable value to future comparative studies of animal development. A dense germ disc is not evident during development in C. salei, but we show that the gastrulation process is similar to that in spider species that do have a dense germ disc. In the opisthosoma, the order of appearance of precursor epithelial invaginations provides evidence for the non-homology of the tracheal and book lung respiratory systems.

No MeSH data available.


Related in: MedlinePlus