THE RESPONSE TO MOLLUSCAN SHELLS OF THE SWIMMING SEA ANEMONES STOMPHIA COCCINEA AND ACTINOSTOLA NEW SPECIES

1967 ◽  
Vol 45 (6) ◽  
pp. 895-906 ◽  
Author(s):  
D. M. Ross ◽  
L. Sutton

Behavior patterns in the sea anemones Stomphia coccinea and Actinostala new species are described by which these animals settled preferentially on shells of Modiolus modiolus (commensal of S. coccinea) after they have been made to swim in response to the appropriate stimuli (the starfishes Dermasterias or Hippasteria, the nudibranch Aeolidia papillosa, etc.). Tentacular and oral contact without adhesion, followed by great distension of the pedal disc and some flexion of the column towards the shell, were the main components of these behavior patterns. Anemones which had been allowed to settle on other surfaces not more than 6 h previously migrated to shells which were brought into contact with the tentacles. Shells which were boiled in alkali to remove organic matter lost their capacity to elicit the response. This behavior pattern is compared with that of Calliactis parasitica, a commensal of hermit crabs which shows a preference for settling on shells of large gastropods.

Author(s):  
Michel Praet-Van

This ultrastructural investigation of gametogenesis in a deep-sea anemone of the Bay of Biscay trawled around 2000 m depth, contributes to the knowledge of biology and strategy of reproduction of deep-sea benthos.This sea anemone is dioecious. The sperm appears very similar to those of shallow water sea anemones of the genus, Calliactis. The ultrastructural investigation of oogenesis allows the characteristics of the stages of previtellogenesis and vitellogenesis to be defined. The latter begins with a period of lipogenesis correlated with the formation of a trophonema. Mature oocytes measure up to 180 (im in diameter. Study of spermatogenesis and oogenesis reveals that spawning occurs in April/May. In males, the main area of testicular cysts, full of sperm, reaches maximal development from March to May and, in females, the percentage of mature oocytes decreases from 33% in April to 1% in May.Spawning may be induced by the advent in the deep-sea of the products of the spring phytoplankton bloom. This period of spawning, during the increased deposition of organic matter to the deep-sea floor, may be an advantageous strategy for early development of Paracalliactis.


Zootaxa ◽  
2012 ◽  
Vol 3244 (1) ◽  
pp. 59 ◽  
Author(s):  
IVAN MARIN ◽  
SERGEY SINELNIKOV

A new species of amphipod from the genus Metopelloides Gurjanova, 1938 (Crustacea: Amphipoda: Stenothoidae) asso-ciated with two species of sublittoral hermit crab species, Pagurus pectinatus (Stimpson, 1858) and Elassochirus cavi-manus (Miers, 1879) (Crustacea: Decapoda: Paguridae), is described from the Russian coasts of the Sea of Japan. The newspecies clearly differs from the congeners by the combination of morphological features such as telson without lateralspines, an elongated mandibular palp with single apical setae, the structures of distoventral palmar margins of subchelaon gnathopods I and II in females, bright white-red body coloration. Thus, the record of Metopelloides paguri sp. nov.represents the second record of the family Stenothoidae in the association with sublittoral hermit crabs from the Sea of Japan.


Zootaxa ◽  
2011 ◽  
Vol 3027 (1) ◽  
pp. 9 ◽  
Author(s):  
DANIEL LAURETTA ◽  
ESTEFANÍA RODRÍGUEZ ◽  
PABLO E. PENCHASZADEH

During 2007, 2008, and 2010, 23 specimens of an undescribed vermiform sea anemone were collected on Punta Pardelas and Fracaso Beach (Península Valdés, Argentina). The specimens have longitudinal rows of cinclides distally, all mesenteries perfect, tentacles hexamerously arranged without acrospheres, column not divisible into regions, no marginal sphincter and no conchula. We describe these specimens as a new species within the genus Harenactis (family Haloclavidae). Harenactis argentina sp. nov. is the second species of Harenactis; it represents the first record of this genus in the southern hemisphere and the first record of a soft bottom-dwelling sea anemone in the Argentine continental zone. Furthermore, we discuss the familial placement and relationships of the genus Harenactis and other athenarian sea anemones.


2021 ◽  
Vol 50 (2) ◽  
pp. 74-95
Author(s):  
Yu.S. Evlakhova ◽  
◽  
E.N. Alifanova ◽  
A.A. Tregubova ◽  
◽  
...  

This paper finds out the behavior patterns of the Russian banking sector and systemically important banks in response to changes in the population financial activity under the economic shocks. The results show that the Russian banking sector has a behavior pattern that includes the sequence of actions: the outflow of deposits — vulnerability to non-repayment of loans — deposit bubble — credit bubble. We find no consistent evidence that systemically important banks show the same sequence of actions during the crises. We also find that the banking sector behavior and systemically important banks’ behavior varied in 2008–2009, but became the same in the crisis of 2014–2015. The coincidence of behavior patterns of the banking sector and systemically important banks increases the systemic risk. Research on intragroup differences between systemically important banks will allow finding solutions to reduce the risk.


PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9603
Author(s):  
Kateřina Kuřavová ◽  
Jan Šipoš ◽  
Petr Kočárek

Detritus (decaying organic matter) and phyllodes of mosses are two main components in the diet of groundhoppers (Orthoptera: Tetrigidae). We studied the energy balance of consumed food under laboratory conditions in the detrito-bryophagous groundhopper, Tetrix subulata (Linnaeus, 1758). The results indicated that the energy food budget of this detrito-bryophagous groundhopper was comparable to those of small herbivorous grasshoppers (Acrididae: Gomphocerinae, Melanoplinae), which have a similar energy food budget of approximately 800–1,100 J/g. T. subulata consumed four times more detritus than mosses, although both components provided similar amounts of energy (ca. 15–16 kJ/g). However, in contrast with detritus, moss fragments passed through the digestive tract without a distinct change in their mass or a loss in their energy value. We assume that moss may cause the longer retention of semifluid mass of partly digested food in the alimentary tract; hence, the digestion and efficiency of nutrient absorption from detritus could be more effective.


Check List ◽  
2018 ◽  
Vol 14 (4) ◽  
pp. 617-629
Author(s):  
José Luis Tello-Musi ◽  
Ricardo González-Muñoz ◽  
Fabián H. Acuña ◽  
Nuno Simões

The sea anemone Calliactis tricolor (Le Sueur, 1817) is an ecologically important member of the benthic community in coastal and coral reefs of the tropical Atlantic, particularly for their propensity to establish mutualistic symbiotic relationships with hermit crabs. This species is presumably distributed throughout the Gulf of Mexico; however, it had never been recorded in the southwestern part of the Gulf. Here we document the first record of C. tricolor in 2 coral reef localities of the Veracruz reef system, Mexico, and update the number of species of sea anemones known for the region.


1970 ◽  
Vol 48 (2) ◽  
pp. 351-357 ◽  
Author(s):  
D. M. Ross

Calliactis polypus (Forskål) lives as a commensal with various pagurids in the Pacific and Indian Oceans. In trials with the Hawaiian species, Dardanus gemmatus, the anemone, unlike the European C. parasitica, displayed only slight activity towards crabs or molluscan shells. As reported previously, crabs display a highly active behavior pattern towards C. polypus, tapping and scratching the column and eventually transferring it to its shell. The mechanical stimuli applied by the crab cause C. polypus to relax so completely that it can be lifted easily off the surface to which it was attached. Unlike C. parasitica and C. tricolor under similar circumstances, C. polypus does not release its pedal disc unaided. The tentacles and pedal disc of the detached C. polypus are extremely sticky and adhere at once to any solid surface presented to them. This enables an anemone detached by a crab to settle quickly on the shell even when only a small area of the pedal disc or only a few tentacles come into contact with the shell when placed there by the crab. The discussion emphasizes these differences in the behavior of closely related species in achieving the same ends. It also stresses that C. polypus, possessing a relatively simple nervous system, displays an impressive repertoire of responses to specific stimuli in its association with its pagurid host.


1971 ◽  
Vol 28 (10) ◽  
pp. 1527-1544 ◽  
Author(s):  
Josephine F. L. Hart

Three hermit crabs, Pagurus caurinus, P. quaylei, and P. stevensae, from British Columbia are described as new. Calastacus quinqueseriatus Rathbun, Paguristes ulreyi Schmitt, Pagurus cavimanus (Miers), P. samuelis (Stimpson), Parapagurus pilosimanus Smith, Munidopsis quadrata Faxon, and Chionoecetes tanneri Rathbun have not been recorded from the area between 48° and 55°N and 123° and 135°W, and also show considerable extensions of the known ranges. Within the confines of the same area, Callianassa gigas Dana, Paguristes turgidus (Stimpson), Pagurus cornutus (Benedict), P. hemphilli (Benedict), Orthopagurus minimus (Holmes), Petrolisthes cinctipes (Randall), Sceleroplax granulata Rathbun, Pinnotheres pugettensis Holmes, P. taylori Rathbun, and Planes marinus Rathbun are reported with extensions to known ranges. Pagurus capillatus (Benedict), P. tanneri (Benedict), Paralomis verrilli (Benedict), and Lithodes couesi Benedict are recorded, apparently for the first time from British Columbia, although known from both north and south of this area.


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