About: Tusk shell is a research topic. Over the lifetime, 3 publications have been published within this topic receiving 21 citations. The topic is also known as: Tusk shell.
TL;DR: Behaviour and morphology of the hermit crab, Pagurus imafukui, which occupies tusk shells in nature, were investigated and a positive correlation was found between the shield length of the crab and the width of the tusk shell.
Abstract: Behaviour and morphology of the hermit crab, Pagurus imafukui, which occupies tusk shells in nature, were investigated. A positive correlation was found between the shield length of the crab and the width of the tusk shell. The uropods were nearly symmetrical, with an average asymmetry index of 0.04, such in contrast with a value of 0.28 for Pagurus filholi, that naturally occupies dextral shells. P. imafukui showed a weak preference for tusk shells over dextral shells. The crabs walked in a parallel pattern, while they adopted a cross pattern when forced to enter dextral shells or were in a shell-less condition. On the contrary, P. filholi individuals walked in a cross pattern when in a tusk shell as well as in a dextral shell. Behaviours of shell entering, copulation, and zoeal release as seen in P. imafukui, are similar to the conditions observed in other species. Nearly symmetrical uropods, preference for non-spiral shells, and the walking style comprising a parallel pattern, are thought to be specific to this hermit crab that lives in non-spiral dwellings. Verhalten und Morphologie des Einsiedlerkrebses Pagurus imafukui McLaughlin & Konishi, 1994 der Scaphopoden-Schalen bewohnt, wurden untersucht. Es wurde eine positive Korrelation zwischen Carapaxlange des Krebses und Breite der Scaphopoden-Schale gefunden. Die Uropoden sind fast symmetrisch. Der Medianwert des Asymmetrie-Indexes betragt 0,04 in deutlichem Gegensatz zu dem von 0,28 bei Pagurus filholi De Man, 1887, der rechtsgewundene Schalen bewohnt. P. imafukui zeigte eine schwache Bevorzugung von Scaphopoden-Schalen im Vergleich mit rechtsgewundenen Schalen. Die Gangart der Einsiedler ist parallel, aber uber Kreuz in schalenlosem Zustand oder in rechtsgewundener Schale. Von P. filholi wird sowohl in Scaphopoden-Schalen als auch in rechtsgewundenen Schalen nur letztere Gangart benutzt. Das Verhalten bei der Inbesitznahme der Schale, bei der Begattung und dem Entlassen der Zoeen gleicht dem bei anderen Arten. Fast symmetrische Uropoden, Bevorzugung ungewundener Schalen und die parallele Gangart werden als Besonderheiten dieser Einsiedler-Art betrachtet, die ungewundene Gehause bewohnt.
TL;DR: In crabs subjected to conditions other than a dextral shell, the otherwise rather short right uropod became somewhat extended, and in those reared in sinistral shells, the right major cheliped was more enlarged.
Abstract: The body of a hermit crab shows asymmetrical morphology, which may be related to utilization of the dextral shell. To examine the effect of the shell, we reared Pagurus filholi (De Man, 1887) from the glaucothoe stage to full-sized adults, in a sinistral shell, in a straight tusk shell, without a shell, and in a normal dextral shell as a control. Body parts that show the most conspicuous asymmetry, uropods, pleopods and chelipeds, were checked at the time of the shedding of exuviae during rearing. No inversion of laterality on these characters was observed. However, in crabs subjected to conditions other than a dextral shell, the otherwise rather short right uropod became somewhat extended, and in those reared in sinistral shells, the right major cheliped was more enlarged.