Morphology of the gastric mill teeth in dotillid crabs (Crustacea: Brachyura: Dotillidae) from Indonesia.

The gastric mill is a prominent structure in the digestive system of brachyuran crabs, consisting of a median tooth plate and a pair of lateral tooth plates. Among crab species that are deposit feeders, the morphology and size of the gastric mill teeth are correlated with the preferred substrate types and food spectrum. In this study, we provide a detailed description of the morphology of the median and lateral teeth of the gastric mills in eight species of dotillid crabs from Indonesia, and compare them in relation to habitat preferences and molecular phylogeny. Ilyoplax delsmani, Ilyoplax orientalis, and Ilyoplax strigicarpus have comparatively simple shapes of their median and lateral teeth, with fewer teeth on each lateral tooth plate compared to Dotilla myctiroides, Dotilla wichmanni, Scopimera gordonae, Scopimera intermedia, and Tmethypocoelis aff. ceratophora, which have more complexly shaped median and lateral teeth, with a greater number of teeth on each lateral tooth plate. The number of teeth on lateral tooth correlates with habitat preference, that is, dotillid crabs inhabiting muddy substrata have fewer teeth on the lateral tooth plate, and those inhabiting sandy substrata have a more teeth. Phylogenetic analysis using partial COI and 16S rRNA genes supports that teeth morphology is similar among closely related species. Therefore, the description of median and lateral teeth of the gastric mill is expected to contribute to the systematic study of dotillid crabs.

Two new species of Tmethypocoelis Koelbel, 1897 (Decapoda, Brachyura, Dotillidae) from Sulawesi, Indonesia.

Tmethypocoelis Koelbel, 1897, is a central Indo-West Pacific genus of small intertidal, soft sediment dotillid crabs that includes five recognised species. Two new species, Tmethypocoelissimplexsp. nov. and T.celebensissp. nov., are here described from Sulawesi, Indonesia. Tmethypocoelissimplexsp. nov. is found on the west coast of Central Sulawesi, while T.celebensissp. nov. occurs in the north-eastern part of Sulawesi. Both new species differ from each other and known congeners by the male cheliped, male pleon, and male first gonopod characters. The differences in gastric mill morphology further confirm the two species as new. The distinct water current patterns in the Makassar Strait and the Maluku Channel might have contributed to the evolution of these two sibling species.

Autochthonous production contributes to the diet of wood-boring invertebrates in temperate shallow water.

Marine wood-boring invertebrates rapidly fragment coarse woody debris in the sea. These wood borers have the ability to digest wood cellulose, but other potential food sources have been less investigated. To assess the contribution of each potential food source to the diet of wood borers, we traced seasonal and environmental changes in δ13C of shipworms cultured under the same experimental conditions and related these changes to variations in δ13C of potential food sources, i.e., wood log and particulate organic matter (POM) by using multiple linear regression models rather than the Bayesian mixing model. Based on the standardized partial regression coefficients in the model, it became clear that wood-derived organic carbon was the main carbon source for the teredinids, and POM also accounted for 37.9% of the teredinids' carbon source. Furthermore, we clarified variations in supplemental nitrogen sources for the teredinids: one species depended on both POM and wood log, whereas the other three species depended on either POM or wood log for their nitrogen source. δ13C values of another wood-boring bivalve of Martesia (Pholadidae) increase as it grows, which suggests that the bivalve switches its feeding strategy from xylophagous to filter feeding as it grows. Wood borers are known to accelerate the transfer of organic materials derived from wood logs to marine ecosystems. However, this study suggests that autochthonous production strongly contribute to the diet of marine wood borers, helping them to decompose wood logs in temperate shallow water.

Crustaceans in changing climate: Global warming and invasion of tropical land hermit crabs (Crustacea: Decapoda: Anomura: Coenobitidae) into temperate area in Japan.

There is currently a strong scientific consensus that recent global change of climate, including the global warming, seriously damage ecosystems of both lands and oceans. Here, I review recent drastic northern expansion of distribution of tropical land hermit crabs (Coenobita) into temperate Japan. Seto Marine Biological Laboratory of Kyoto University has a long history (97 years) and has been conducting various programs of long-term monitoring survey on coastal biota. A part of the results is also introduced here. Seventeen species of land hermit crabs are known from tropical regions worldwide, and seven species are known in Japan, which are mainly distributed in tropical region of Japan. Recent intensive studies on coastal areas of Japan have shown that many juveniles and small individuals of land hermit crabs are found during warm season in temperate regions. The finding of the species that were identified by DNA analysis as Coenobita rugosus and C. purpureus might be an indication for the global warming effect. Further, I here introduce the model of northern limit of distribution proposed by Gorodkov (1986) which explains change of detailed structure of population toward the limit of distribution. Moreover, I here propose the model of stages of adaptation of tropical species to temperate zone through ecological and evolutional times. These two models are useful and helpful to understand the things happen in populations in the limit of distribution and, therefore, useful for conservation of species and biological communities.

Reproductive Aggregations of Dynoides dentisinus (Crustacea: Peracarida), an Intertidal Isopod with Remarkable Sexual Dimorphism.

AbstractThe intertidal isopod Dynoides dentisinus is a sexually dimorphic species; males are much larger than females and have a large, horn-like pleonal process (hereafter referred to as a "horn") and large, posteriorly extended uropods. Here, we investigated the function of these structures with regard to their mating system. Behavioral interactions were observed between a male occupying a small tube (resident) and a newly introduced individual (a female or male visitor). When the visitor was male, the resident repeatedly struck the visitor with his horn; each swing was accompanied by a short sound produced by stridulation. The resident also used his uropods to strike the male visitor and then rejected the visitor. The resident struck the female visitor in a similar fashion but eventually accepted her into the tube; during this process, the resident frequently emitted stridulatory sounds. Our field survey found that the members shared a single shelter (barnacle shell) containing groups composed of several males and females. This suggests that the mating system of this species is polygynandry. The number of females in a single barnacle shell was positively associated with the basal diameter of the barnacle shell. However, the number of females was not associated with the body size, horn size, or uropod size of the largest male in the barnacle shell. These results suggest that male body size, horns, and uropods might have evolved as weapons through male-male competition for large barnacle habitats and more females, but that they have not evolved as ornaments via female choice.

A Brief Description of Surface Structure and Composition of the Pseudo-Snail Shell Formed by a Sea Anemone Stylobates sp. Symbiotic with Hermit Crabs from the Deep-Sea Floor.

Sea anemones belonging to the genera Adamsia and Stylobates have a remarkable symbiotic relationship with hermit crabs. These symbiotic sea anemones produce a shell-like structure, called a "carcinoecium," that covers and extends over the gastropod shell of the host hermit crab as hermit crabs grow. This structure has been described as "chitinous carcinoecium" or "chitinous coating." A previous study investigated carcinoecia of Stylobates aeneus, the results of which indicated that it contained at least 1.7% chitin, while the remaining components were unidentified. Moreover, the microscopic structure of a carcinoecium still remains to be detailed. We, therefore, conducted detailed observations using a stereoscopic microscope and scanning electron microscope (SEM) and the analyses of the chemical composition of carcinoecia produced by Stylobates sp. (apparently conspecific with Isadamsia sp. "J" reported in Uchida and Soyama, 2001) associated with a pagurid hermit crab Pagurodofleinia doederleini collected in the south of the Shima Peninsula, Mie, Honshu Island, Japan at a depth of 294-306 m. Our results indicate that carcinoecia of Stylobates sp. contain HCl-soluble components (13%), NaOH-soluble components (38%), chitin (11%) and unidentified remnants (39%). Additionally, our observations show that Stylobates sp. incorporates dark- and white-colored particles that could be sand and/or mud into the carcinoecium.

Morphology and Habitats of the Hermit-Crab-Associated Calyptraeid Gastropod Ergaea walshi.

Ergaea walshi, a gastropod with a markedly flat shell, often lives inside empty snail shells occupied by hermit crabs. We investigated its lifestyle, shell growth pattern, and habitat preference for host hermit crabs and host snail shells. Four hundred sixteen snail shells, including 363 shells with hermit crabs and 53 empty shells, were collected from intertidal zones of sandy and muddy flats around Kii Peninsula, Japan. The specimens comprised seven hermit crab species occupying 24 shell species; E. walshi was harbored in 13.2% of snail shells with hermit crabs and 17.0% of those without hermit crabs. Although no preference was detected for particular species of hermit crab or snail shell, E. walshi preferred to live inside of snail shells with wider apertures used by comparatively bigger hermit crabs. This suggests that the occurrence of E. walshi was influenced by host size rather than host species. When looking at growth patterns, we found that the attached shell portion of E. walshi continued to be enlarged horizontally, while growth in shell height slowed at approximately 5.0 mm. The conspicuously flattened shell of E. walshi is considered as a growth pattern for adapting to the narrow space within the snail shell occupied by hermit crabs. Consistent with this idea, our comparison of shell growth patterns in 23 calyptraeid species showed that shell of E. walshi is the flattest in this family.

Molecular phylogeny of ten intertidal hermit crabs of the genus Pagurus inferred from multiple mitochondrial genes, with special emphasis on the evolutionary relationship of Pagurus lanuginosus and Pagurus maculosus.

The hermit crab genus Pagurus exhibits high species diversity and a wide geological distribution. Despite the high species diversity of hermit crabs in the western Pacific coast of Japan, molecular phylogenetic studies of these species have yet to be conducted. To investigate their molecular phylogeny and genetic diversity, we obtained nearly complete mitochondrial genome sequences for ten Pagurus species found along the Pacific coast of Japan by next-generation sequencing, which were compared to other congeners deposited in the GenBank database. The genomes ranged from 13,458 to 16,401 base pairs in length, possessing 13 protein-coding genes, 2 rRNAs, and 22 tRNA genes. Based on the reconstructed phylogeny, we found that (1) Japanese Pagurus species separated into three groups, nested within the Northern Pacific species. (2) Pagurus lanuginosus and Pagurus maculosus, showed high morphological similarities, implying close kinship. Indeed, these two species were genetically closest to each other, compared to the remaining species studied. (3) An unspecified specimen sampled from the deep sea, which morphologically resembled Pagurus, might be a member of the Pagurus genus, but is genetically distant from the other Japanese Pagurus species. The novel data reported here may provide new perspectives for systematic studies of hermit crabs; these results provide important information that will facilitate population-level research and identifying intraspecific variation of these non-model, but ecologically important, decapod species.

The complete larval development of Pagurus maculosus Komai & Imafuku, 1996 (Decapoda, Anomura, Paguridae) reared in the laboratory, and a comparison with sympatric species.

The complete larval development of the hermit crab Pagurus maculosus, is described and illustrated based on specimens reared in the laboratory at 15 °C and 33-35 PSU. Newly hatched larvae invariably passed through a short prezoeal stage (10 minutes to 2 hours), four zoeal stages (each of 7 days,) and one megalopal stage (14 days). Distinct morphological features of each larval stage of the present study are compared with other closely related species in Japanese waters, and we found many differences in morphology and the duration of zoeal stages between them. We mentioned significant diagnostic characters separating this species from other congeners in Japanese waters that include the presence of red-yellowish chromatophores on the maxillipeds. This is the first report of complete larvae development of Pagurus maculosus.

The complete larval development of Pagurus lanuginosus De Haan, 1849 (Decapoda, Anomura, Paguridae) reared in the laboratory, with emphasis on the post-larval stage.

The complete larval development of Pagurus lanuginosus is described and illustrated including the first description of the post-larval stage. Specimens were reared in the laboratory at 15°C and 33.5-35.02 PSU. Newly hatched larvae passed through a short prezoeal stage (10 minutes to 2 hours), four zoeal stages (6, 6, 6, 8 days), and one megalopal stage (10 days). We compared the morphological features of each larval stage with those of the preceding two descriptions on the same species, and found many differences in morphology and the duration between zoeal stages. We concluded that significant diagnostic characters separating this species from other congeners in Japanese waters include the presence of two pairs of yellowish chromatophores on the carapace in the zoeal stages, a translucent body flecked with red chromatophores, and two pairs of red chromatophores on the carapace in the megalopal stage. 

A new species of Fizesereneia Takeda & Tamura, 1980 (Crustacea: Decapoda: Brachyura: Cryptochiridae) from Japan.

A new species of pit crab of the genus Fizesereneia Takeda & Tamura, 1980, Fizesereneia daidai sp. nov., is described and illustrated based on specimens collected from the scleractinian corals Micromussa amakusensis and Micromussa sp. in Japan. The new species, the sixth assigned to the genus, can be separated from its congeners by having an orange posterior carapace in life, a subrectangular carapace, the width to length ratio of the carapace depressions being approximately three-halves, the midline of the carapace depression being almost invisible in lateral view, and the ocular peduncles being mostly exposed. The usefulness of the fusion or separation of the pterygostomial region to the carapace as a generic character is discussed.

Hermit crabs perceive the extent of their virtual bodies.

A flexible body image is required by animals if they are to adapt to body changes and move effectively within a structurally complex environment. Here, we show that terrestrial hermit crabs, Coenobita rugosus, which frequently change shells, can modify walking behaviour, dependent on the shape of the shell. Hermit crabs walked along a corridor that had alternating left and right corners; if it was narrow at the corner, crabs rotated their bodies to avoid the wall, indicating an awareness of environmental obstacles. This rotation increased when a plastic plate was attached to the shell. We suggest that the shell, when extended by the plate, becomes assimilated to the hermit crab's own body. While there are cases of a tool being assimilated with the body, our result is the first example of the habitat where an animal lives and/or carries being part of a virtual body.

Influence of the distribution of emphysema on diaphragmatic motion in patients with chronic obstructive pulmonary disease.

PURPOSE: We investigated whether the distribution of emphysema on computed tomography (CT) images can affect chest wall motion in patients with chronic obstructive lung disease (COPD). MATERIALS AND METHODS: The subjects were 35 male patients with COPD (age, 69.7 ± 6.2 years). The RA-950 (the ratio of lung volume under -950 HU to total lung volume on CT) was measured separately for the upper and lower halves of the lung. We analyzed the flatness of the diaphragm (Kdome) and its motion (ΔLappo) using dynamic magnetic resonance imaging. Paradoxical motion (Mpr) represented the ratio of the paradoxical diaphragmatic movement (downward or upward) when the lung area decreased or increased, respectively, to he total diaphragm movement (expressed as a percent). These parameters were analyzed in correlation with pulmonary function tests and St. George Respiratory Questionnaire (SGRQ) scores. RESULTS: The RA-950 of the lower lung zone correlated significantly with the Kdome (P = 0.033), ΔLappo (P = 0.006), Mpr (%) (P = 0.001), forced expiratory volume at 1 s (% predicted; P < 0.001), and activity score of the SGRQ (p = 0.017). The RA-950 of the upper lung zone did not correlate with these parameters. CONCLUSION: In COPD patients, the distribution of emphysema on CT correlates with airflow obstruction and abnormal diaphragmatic motion.

Pneumothorax and idiopathic pulmonary fibrosis.

PURPOSE: We evaluated the relation between the severity of idiopathic pulmonary fibrosis (IPF) and the incidence of pneumothorax on computed tomography (CT) images. MATERIALS AND METHODS: In this retrospective study, we evaluated the presence of pneumothorax in 56 consecutive patients who died of IPF from the initial CT to death. We quantitatively analyzed a total of 207 CT images and measured the volume of the normal pattern (N-pattern) and each lesion pattern on the initial CT and their serial changes. The effects of pneumothorax and clinical and CT features on survival were evaluated using Cox regression analysis. RESULTS: Pneumothorax occurred in 17 of 56 patients. Comparison of the pneumothorax (+) and (-) groups showed the initial vital capacity (VC) was lower (P = 0.005) and the follow-up period was shorter (P = 0.03) in the former group. The decrease in the N-pattern volume in the pneumothorax(+) group was significantly faster than in the pneumothorax(-) group (P = 0.013). Cox regression analyses identified a rapid decrease in N-pattern volume (P = 0.008) and a rapid decrease in VC (P = 0.002), but not pneumothorax, as significant predictors of poor survival. CONCLUSION: Pneumothorax in IPF patients is associated with lower VC and rapid deterioration of CT findings. The findings suggest that pneumothorax is a complication of advanced IPF.

Assessment of prognosis of patients with idiopathic pulmonary fibrosis by computer-aided analysis of CT images.

PURPOSE: To present the Gaussian Histogram Normalized Correlation (GHNC) system, to quantify the extent of disease on computed tomography (CT) images of idiopathic pulmonary fibrosis (IPF), and to assess its utility by comparing the radiologist' scoring and prognosis. MATERIALS AND METHODS: GHNC was used to analyze baseline thin-section CT images (30-60images per patients) of 40 patients with IPF. It classified the CT lung field into normal (N), ground-glass opacities (G), consolidation (C), emphysema (E) and fibrosis (F) patterns [the latter was also subdivided into reticular (F1) and honeycomb (F2) patterns], then the relative lung volume and relative each pattern volume (area multiplied by slice thickness and interval and divided by predicted total lung capacity) were estimated. The radiologists estimated the area of these patterns on 4 slices per patient; the average was regarded as total extent of each pattern. We compared the estimates determined by radiologists and GHNC with pulmonary function tests, and used Cox regression analysis to examine the relationships between the volumes and patient survival. RESULTS: The area of each pattern measured by GHNC correlated significantly with that estimated by the radiologist on 160 images (P<0.001, each). The volumes of N-pattern and F-patterns are measured by GHNC correlated with carbon monoxide diffusing capacity.During the follow-up (mean 49 mo), 24 patients died. Relative lung volume, N-pattern, F-pattern and F2-pattern correlated with survival in univariate analysis. Multivariate analysis identified F2-pattern volume by GHNC (P=0.034) as a significant predictor of survival. CONCLUSIONS: The GHNC provides automatic measurement of volume of fibrosis. The F2-pattern on CT can predict prognosis of patients with IPF.

Correlation of lung parenchymal MR signal intensity with pulmonary function tests and quantitative computed tomography (CT) evaluation: a pilot study.

PURPOSE: To evaluate the effect of ventilatory impairment on MR signal intensity of the lung parenchyma. MATERIALS AND METHODS: Subjects were five normal volunteers (age = 30 +/- 7.9 years, mean +/- SD) and 19 male patients with chronic obstructive lung disease (COPD) (mean age = 70.4 +/- 6.5 years). Coronal MR images were obtained over entire lung fields at full inspiration and full expiration with cardiac triggering on a 1.5T system. Changes in the mean lung intensity between the two respiratory states were normalized by each intercept of the linear regression lines of the signal changes, and the slope of the relationship was calculated. Computed tomography (CT) images were also obtained in COPD patients at full inspiration using a multidetector row CT scanner. Attenuation values less than -950 Hounsfield units (HU) (RA-950) represented the percentage of relative lung area on the CT. RESULTS: The mean slope of COPD patients (0.365 +/- 0.074) was less steep than that of the normal subjects (0.570 +/- 0.124, P < 0.001). In COPD patients, the slope correlated significantly with forced expiratory volume in one second (FEV1, r = 0.508, P = 0.026), but not with RA-950. CONCLUSION: In COPD patients, lung signal change measured by MRI correlates with airflow obstruction, but not with volume of the emphysema measured by lung CT.

Biotin synthase of Bacillus subtilis shows less reactivity than that of Escherichia coli in in vitro reaction systems.

The biotin synthases of Bacillus subtilis and Escherichia coli were compared in a physiological reduction system using cell-free extracts and in a artificial reduction system using photo-reduced deazariboflavin. The biotin synthase of B. subtilis was less active than that of E. coli in both reaction systems and showed at least ten-fold less biotin-forming activity than that of E. coli in the artificial reduction system. The physiological reduction system using the biotin synthases and cell-free extracts of B. subtilis and E. coli showed species specificity. The results suggest that the activity of the physiological reduction system of B. subtilisis weaker than that of E. coli. Addition of excess dethiobiotin inhibited biotin formation by growing cells of B. subtilis, but not by E. coli.