scholarly journals The taxonomy and apparatus structure of the Silurian distomodontid conodont <i>Coryssognathus</i> Link & Druce, 1972

1993 ◽  
Vol 12 (2) ◽  
pp. 241-255 ◽  
Author(s):  
C. Giles Miller ◽  
Richard J. Aldridge
Keyword(s):  
Feeding Apparatus ◽  
Crown Tissue

Abstract. Collections of discrete conodont elements from the Upper Whitcliffe Formation of the Welsh Borderland indicate a septimembrate plan for the feeding apparatus of Coryssognathus, comprising Pa, Pb, Pc, M, Sa/Sb, Sb and Sc elements. Each element is paired, and relative frequencies suggest that there was a total of 16 elements in the apparatus, including two indistinguishable pairs of Sc elements. Associated small coniform elements appear to represent discrete denticles of crown tissue that were sequentially incorporated into multidenticulate elements during ontogeny.

scholarly journals Brachial supporting structure of Spiriferida (Brachiopoda)

2020 ◽  
pp. 1-15
Author(s):  
Zhiwei Yuan ◽  
Wen Guo ◽  
Dan Lyu ◽  
Yuanlin Sun
Keyword(s):  
Mantle Cavity ◽  
Family Type ◽  
Type I ◽  
Type Ii ◽  
Feeding Apparatus ◽  
Single Family ◽  
Supporting Structure ◽  
Type Iii ◽  
Type Iv ◽  
Evolutionary Lineages

Abstract The filter-feeding organ of some extinct brachiopods is supported by a skeletal apparatus called the brachidium. Although relatively well studied in Atrypida and Athyridida, the brachidial morphology is usually neglected in Spiriferida. To investigate the variations of brachidial morphology in Spiriferida, 65 species belonging to eight superfamilies were analyzed. Based on the presence/absence of the jugal processes and normal/modified primary lamellae of the spiralia, four types of brachidium are recognized. Type-I (with jugal processes) and Type-II (without jugal processes), both having normal primary lamellae, could give rise to each other by losing/re-evolving the jugal processes. Type-III, without jugal processes, originated from Type-II through evolution of the modified lateral-convex primary lamellae, and it subsequently gave rise to Type-IV by evolving the modified medial-convex primary lamellae. The evolution of brachidia within individual evolutionary lineages must be clarified because two or more types can be present within a single family. Type-III and Type-IV are closely associated with the prolongation of the crura, representing innovative modifications of the feeding apparatus in response to possible shift in the position of the mouth towards the anterior, allowing for more efficient feeding on particles entering the mantle cavity from the anterior gape. Meanwhile, the modified primary lamellae adjusted/regulated the feeding currents. The absence of spires in some taxa with Type-IV brachidium might suggest that they developed a similar lophophore to that in some extant brachiopods, which can extend out of the shell.

The Feeding Apparatus in four Pacific Tube Blennies (Te/eos fei: Chaenopsidae):.

1986 ◽  
Vol 7 (3) ◽  
pp. 241-253 ◽  
Author(s):  
Kurt Kotrschal ◽  
David G. Lindquist
Keyword(s):  
Feeding Apparatus

Larval development of Metapenaeopsis barbata (de Haan, 1844) (Crustacea: Decapoda: Penaeidae)

1997 ◽  
Vol 48 (5) ◽  
pp. 401 ◽  
Author(s):  
Jesse D. Ronquillo ◽  
Toshio Saisho
Keyword(s):  
Morphological Characteristics ◽  
Larval Feeding ◽  
Feeding Apparatus ◽  
Filter Feeder ◽  
Closely Related Species ◽  
Larval Stages ◽  
Chaetoceros Gracilis ◽  
The Family ◽  
Gravid Females ◽  
Natural Means

Gravid females of Metapenaeopsis barbata spawned in the laboratory by natural means and the larvae were reared from hatching to postlarval stage at 27·0–29·8˚C and 33·5–34·5 g kg -1 salinity. The larvae metamorphosed into first postlarvae, with a survival rate of up to 98·4%, after about 10 days following hatching and subsistence on only an algal diet of Tetraselmis tetrathele and Chaetoceros gracilis. Six naupliar stages, three protozoeal stages, three mysis stages and the first postlarval stage are described and illustrated. On the basis of morphological characteristics, larval stages of M. barbata can be distinguished from similar stages of closely related species in the family Penaeidae. As inferred from the morphology of the larval feeding apparatus, M. barbata is still a filter-feeder even at the first postlarval stage.

Effect of N Fertilization on Sugarbeet Crown Tissue Production and Processing Quality 1

1978 ◽  
Vol 70 (5) ◽  
pp. 876-880 ◽  
Author(s):  
A. D. Halvorson ◽  
G. P. Hartman ◽  
D. F. Cole ◽  
V. A. Haby ◽  
D. E. Baldridge
Keyword(s):  
N Fertilization ◽  
Processing Quality ◽  
Crown Tissue ◽  
Tissue Production

Design of a Novel Quantitative Powder Feeding Apparatus

2021 ◽  
Vol 45 (8) ◽  
pp. 657-666
Author(s):  
Yu-Ting Wu ◽  
Zhen Qin ◽  
Yunseung Lee ◽  
Sungki Lyu ◽  
Seoungho Back ◽  
...  
Keyword(s):  
Feeding Apparatus ◽  
Powder Feeding

Memoirs: The Development of the Serpiilid Pomatoeeros Triqueter L

1941 ◽  
Vol s2-82 (327) ◽  
pp. 467-540 ◽  
Author(s):  
F. SEGROVE
Keyword(s):  
Body Wall ◽  
Feeding Activity ◽  
Dorsal Surface ◽  
The Body ◽  
Single Pair ◽  
Feeding Apparatus ◽  
Food Material ◽  
Locomotor Apparatus ◽  
Adult Feeding ◽  
Branchial Crown

1. The larvae of Pomatoceros triqueter L. were obtained by artificial fertilization and reared through metamorphosis and for several months afterwards. Larval development took three weeks in summer, and about the same time in winter when the temperature was maintained at 65° F. 2. The eggs are small and give rise to typical trochosphere larvae with well-developed prototroch, metatroch, neurotroch, and feeding cilia, a spacious blastocoelic body-cavity and paired protonephridia. A head-vesicle and a conspicuous anal vesicle are also present. The right eye develops before the left. The larva is very active and grows rapidly at the expense of collected food material. 3. Three setigerous segments arise simultaneously; a fourth is added prior to metamorphosis. The lateral collar-folds develop in two capacious pockets which arise by invagination of the body-wall behind the metatroch, the ventral collar-fold by outgrowth of the ventral body-wall. The rudiments of the thoracic membrane appear above the lateral collar-folds. 4. Metamorphosis commences with the shrinkage of the locomotor apparatus, which leads to the exposure of the lateral collar-folds. The larva settles to the bottom and creeps about on its ventral surface by means of the neurotroch. The branchial crown arises as tripartite outgrowths on the sides of the head. The remaining tissues of the head, apart from the cerebral ganglion and eyes, are gradually resorbed. No tissue is thrown off. 5. The neurotroch gradually disappears and is replaced by cilia on the dorsal surface. The worm begins to secrete a calcareous tube. The resorption of the head is completed and the mouth assumes a terminal position surrounded by the branchial crown. 6. A fourth pair of filaments is added to the branchial crown. The dorsal pair of filaments develops into 'palps'. The third filament on the left side is modified as the operculum; the remaining filaments develop pinnules. 7. Further segments are added to the trunk. Those first added are of the thoracic type from the beginning. The eighth and succeeding setigers are of the abdominal type. The thoracic membrane gradually extends backwards to the posterior end of the thorax. 8. The thoracic nephridia arise as a single pair of cells which give rise to the dorsal unpaired duct by outgrowth. 9. The influence of the egg on the course of development is discussed. It is suggested: (a) that the small size of the egg is responsible for the active habits and protracted pelagic life of the larva; (b) that the mode of development of the collar is significant in that interference with the locomotor and feeding apparatus is thereby avoided; (c) that the general shrinkage which occurs at metamorphosis is related to a suspension of feeding activity in the period between the degeneration of the larval and the establishment of the adult feeding apparatus. 10. The development of Pomatoceros is compared with that of the Serpulid Psygmobranchus and the Sabeilid Branchiomma.

Sign in / Sign up

Export Citation Format

Share Document