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2. Chaetotaxy applied to Norwegian Gyrodactylus salaris Malmberg, 1957 (Monogenea) clades and related species from salmonids
- Creator:
- Bakke, Tor A., Nilsen, Kariann B., and Shinn, Andrew P.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Gyrodactylus salaris, parasite, salmonids, taxonomy, and chaetotaxy
- Language:
- English
- Description:
- Gyrodactylus salaris Malmberg, 1957 is a major pathogen of wild Salmo salar L. parr populations in Norway, and its delimitation from non-pathogenic species is important. The present study was undertaken to test the power of chaetotaxy to differentiate between three populations belonging to both the same and different clades (as stated by mtDNA) of G. salaris, in addition to three different species of gyrodactylids (G. salaris, G. thymalli and G. caledoniensis). The gyrodactylids were processed for chaetotaxy in situ and a maximum of 50 specimens per collection site were used to construct a generalised map over the sensilla. The sensilla were found in all populations to be symmetrically distributed around the median longitudinal axis, according to a formula of 7 dorsal (34 sensilla) and 8 ventral (44 sensilla) clusters on each side of the median line. The three Norwegian populations of G. salaris were found identical, as were the population of G. thymalli. The specimens of G. caledoniensis from Scotland, however, were found to differ from the Norwegian species G. salaris and G. thymalli by the position of one sensillum in two of the clusters. A comparison of the sensillum pattern of laboratory maintained G. salaris (River Lierelva) with results obtained ten years earlier, questions the temporal stability of the chaetotaxy pattern. The present results indicate that chaetotaxy can be used to discriminate between certain Gyrodactylus spp. but not generally.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3. Chaetotaxy of the monogeneans Macrogyrodactylus clarii and M. congolensis from the gills and skin of the catfish Clarias gariepinus in Egypt, with a note on argentophilic elements in the nervous system
- Creator:
- El-Naggar, Mohammed M., Arafa, Safaa Z., El-Abbassy, Sameer A., and Kearn, Graham C.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Monogenea, Macrogyrodactylus clarii, Macrogyrodactylus congolensis, surface sensilla, nervous system, chaetotaxy, and Clarias gariepinus
- Language:
- English
- Description:
- A comparison has been made between the chaetotaxy of the gyrodactylid monogeneans Macrogyrodactylus clarii Gussev, 1961 and M. congolensis (Prudhoe, 1957) Yamaguti, 1963 from the gills and skin, respectively, of the catfish Clarias gariepinus (Burchell) from the river Nile in Egypt. Bilaterally arranged argentophilic structures on the surface of these parasites are presumed to be sensilla and are more abundant in M. clarii than in M. congolensis especially on the ventral surface (124 vs. 66). In both species these sensilla are concentrated on the head lobes and in the pharyngeal region, but there are features of the sensilla patterns that can be used to distinguish the two species. Comparison is made with sensilla patterns of other gyrodactylids. A system of cells and dendritic processes, most probably part of the nervous system, also has an affinity for silver in the two species. There are no previous records of extensive argentophilic elements in the nervous systems of monogeneans.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
4. Description of the larval stages of Gymnochthebius jensenhaarupi and phylogenetic analysis of the relationships with other species of the subfamily Ochthebiinae (Coleoptera: Hydraenidae)
- Creator:
- Delgado, Juan A: and Archangelsky, Miguel
- Type:
- article, model:article, and TEXT
- Subject:
- Coleoptera, Hydraenidae, Ochthebiinae, Gymnochthebius, larvae, chaetotaxy, phylogeny, Argentina, and Neotropics
- Language:
- English
- Description:
- The three larval instars of Gymnochthebius jensenhaarupi (Knisch, 1924) are described and illustrated, including a detailed analysis of their chaetotaxy and porotaxy. The specimens used in this study were collected with adults of G. jensenhaarupi and have been identified as such by association. Comparative notes on the morphology of these larvae with other species of the subfamily Ochthebiinae are given. A hypothesis of phylogenetic relationships between G. jensenhaarupi and other members of Ochthebiinae with thoroughly described larvae is presented. The monophyly of Ochthebiinae is supported by additional larval features. On the other hand Ochthebius, as currently composed, seems to by paraphyletic. Gymnochthebius Orchymont, 1943 is confirmed as the sister group of Aulacochthebius Kuwert, 1887.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
5. Descriptions of larvae of Megadytes (Coleoptera: Dytiscidae: Dytiscinae): The hypothesis of monophyletic origin revisited
- Creator:
- Michat, Mariano C.
- Type:
- article, model:article, and TEXT
- Subject:
- Coleoptera, Dytiscidae, Megadytes, larval morphology, chaetotaxy, and phylogeny
- Language:
- English
- Description:
- The three larval instars of Megadytes (Paramegadytes) glaucus (Brullé, 1838) and the third-instar larvae of M. (Bifurcitus) magnus Trémouilles & Bachmann, 1980 and M. (Trifurcitus) robustus (Aubé, 1838) are described and illustrated for the first time, with particular emphasis on the morphometry and chaetotaxy. A key to the subgenera of Megadytes Sharp, 1882 is presented. In a cladistic analysis of third-instar larval characters, Megadytes is resolved as non-monophyletic; the species of Cybistrini studied, except those included in the subgenus Trifurcitus Brinck, 1945, share three synapomorphies: (i) medial projection of frontoclypeus truncate apically, with many apical setae directed forwards; (ii) lateral projections of frontoclypeus project forwards, not flattened; and (iii) median process of prementum rounded apically. The clade composed of the subgenera Megadytes s. str., Paramegadytes Trémouilles & Bachmann, 1980 and Bifurcitus Brinck, 1945 along with Cybister lateralimarginalis (De Geer, 1774) is well supported by three synapomorphies: (i) head capsule subrectangular and (ii) distal third of mandible more strongly projected inwards, (iii) with a ring of long, hair-like setae. The two species of the subgenus Paramegadytes have bilobed lateral projections on the frontoclypeus. Megadytes (M.) marginithorax (Perty, 1830) is characterized by the very narrow notches between the medial and lateral projections of frontoclypeus. No synapomorphies were discovered to group together the two species of the subgenus Bifurcitus.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
6. Descriptions of larvae of Megadytes (Coleoptera: Dytiscidae: Dytiscinae): The subgenera Trifurcitus and Megadytes s. str., ground plan of chaetotaxy of the genus and phylogenetic analysis
- Creator:
- Michat, Mariano
- Type:
- article, model:article, and TEXT
- Subject:
- Diving beetles, Dytiscidae, Cybistrini, Megadytes, Trifurcitus, larva, chaetotaxy, ground plan, and phylogenetic relationships
- Language:
- English
- Description:
- The three larval instars of Megadytes (M.) carcharias Griffini and M. (Trifurcitus) fallax (Aubé) are described and illustrated in detail for the first time, with an emphasis on morphometry and chaetotaxy of the cephalic capsule, head appendages, legs, last abdominal segment and urogomphi. The ground plan of chaetotaxy of the genus Megadytes Sharp is described and illustrated based on three of the four recognised subgenera. First-instar larvae of Megadytes are characterised by the presence of a large number of additional sensilla on almost every part of the body. Primary chaetotaxy of the subgenera (Bifurcitus Brinck based on third instar) is very similar, with few differences including (1) shape of the setae on the anterior margin of the frontoclypeus; (2) presence or absence of a ring of multi-branched setae on distal third of mandible; and (3) number of setae on the urogomphus. A cladistic analysis of Dytiscidae, based on 169 larval characters and 34 taxa, indicates that: (1) Trifurcitus Brinck deserves generic status; (2) Cybistrini are not closely related to Hydroporinae; (3) the absence of a galea in Cybistrini is a secondary loss independent of that in Hydroporinae; (4) Cybistrini are well supported by many characters (including several aspects of first-instar chaetotaxy).
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
7. Functional and phylogenetic components in cercarial nervous systems
- Creator:
- Bogéa, Tami
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- cercarial sensory receptors, chaetotaxy, cholinergic network, ultrastructure, site-specificity, taxonspecificity, functional morphology Crepidostomum Braun, 1900, lecithodendriid Allassogonoporus Olivier, 1938 and opecoelid Allopodocotyle Pritchard, and 1966 were
- Language:
- English
- Description:
- Studies involving comparisons of taxa that vary in their degree of relatedness may allow the distinction of functional and phylogenetic components in cercarial sensory systems. In this study, cercariae of allocreadiids Bunodera Railliet, 1896 and Crepidostomum Braun, 1900, lecithodendriid Allassogonoporus Olivier, 1938 and opecoelid Allopodocotyle Pritchard, 1966 were compared as regards ultrastructure and chaetotaxy of sensory receptors as well as neuromorphology. Cercariae were treated with acetylthiocholine iodide and silver nitrate and some were processed for scanning and transmission electron microscopy. The types of cercarial sensory receptors differed in the presence of a tegumentary sheath, a dome-like base and a tegumentary collar, number of cilia (0, 1, 2 or more), cilium length (short, moderately long or long) and tegumentary collar length (low to moderately low, high or very high). Chaetotaxic patterns were consistent at the family level in all taxa studied. Irregular cholinergic nerve networks were identified. The present study indicates that the major categories of cercarial sensory receptors are nonciliated (including sheathed and subtegumentary types) and ciliated (including uncollared and collared types) receptors. It also allows the distinction of functional and phylogenetic components in the sensory systems of the cercariae studied. Functional components were reflected in the numbers of sensory receptors associated with each nerve region and in the ultrastructure and site-specificity of receptor types. Phylogenetic components included taxon-specific chaetotaxic patterns and receptor types.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
8. Larval morphology of Heterogynis (Lepidoptera: Heterogynidae)
- Creator:
- Vegliante , Francesca and Zilli, Alberto
- Type:
- article, model:article, and TEXT
- Subject:
- Zygaenoidea, Heterogynidae, larval morphology, chaetotaxy, and phylogenetics
- Language:
- English
- Description:
- The external morphology and chaetotaxy of the larvae of Heterogynidae (Lepidoptera) are described in order to provide information of potential phylogenetic value for the reconstruction of the systematic relationships within the Zygaenoidea. The most outstanding characteristics of heterogynid larvae are their modified habitus during diapause, the presence of an epipharyngeal lamella, the shape of the prothoracic shield, the presence in the first instar of an organ of unknown function on the middorsum of the mesothorax ("Chapman's organ"), the absence of V2, V3 and Va on the head, the absence of V1 on the prothorax and the presence of two primary setae on the inner side of the proleg, the last trait representing an autapomorphy of the family. A number of possible synapomorphies with the Zygaenidae (e.g. presence of cuticular cavities) suggest a close relationship between these two families, but other larval and adult traits are shared only with the "Phaudinae" and limacodid-group families of the Zygaenoidea (viz. absence of V1 on the prothorax with the "Phaudinae", reduced proboscis and absence of ocelli with them all). Nevertheless, a lack of knowledge of the preimaginal instars of species from some zygaenoid families, and of the homology and polarity of given characters of groups within and outside the Zygaenoidea, hamper a thorough comparison of larvae.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
9. Larval morphology of three species of Hygrobiidae (Coleoptera: Adephaga: Dytiscoidea) with phylogenetic considerations
- Creator:
- Alarie, Yves, Beutel, Rolf G., and Watts, Chris H.S.
- Type:
- article, model:article, and TEXT
- Subject:
- Hygrobiidae, Hydradephaga, larvae, morphology, phylogeny, and chaetotaxy
- Language:
- English
- Description:
- A provisional larval groundplan of the family Hygrobiidae is provided through descriptions of internal and external features of three of six extant species, Hygrobia hermanni (Fabricius, 1775), H. wattsi Hendrich 2001 and H. australasiae (Clark, 1862) and phylogenetic interpretations. Hygrobiidae larvae are morphologically differing dramatically from all other known Adephaga by 20 autapomorphies. Structures involved with feeding, i.e., mouthparts, prepharynx and foregut are highly modified as a result of a specialisation on small tubificid worms and chironomid larvae. A placement of Hygrobiidae within Dytiscoidea is well supported by the reduced condition of the terminal abdominal segments, and the presence of 10 ancestral setae on femur and a clade comprising Hygrobiidae, Amphizoidae, and Dytiscidae by the presence of thin and elongate caudal tentorial arms, a very strong musculus verticopharyngalis and a longitudinally divided adductor tendon of the mandible. A highly modified foregut, reduced terminal spiracles VIII and the presence of tubular gills are features which distinguish hygrobiid larvae from those of other groups of Dytiscoidea (i.e, Amphizoidae, Noteridae, Dytiscidae). A sister-group relationship between Hygrobiidae and Dytiscidae is indicated by a distinctly shortened and transverse prepharynx and a cerebrum and suboesophaeal ganglion shifted to the anterior third of the head. Larvae of the Australian species H. wattsi and H. australasiae share the presence of a bluntly rounded mandible and an apical position of the primary pore MNd in instar I as potential synapomorphies.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
10. On the systematic position of the diving-beetle genus Pachydrus (Coleoptera: Dytiscidae: Hydroporinae): Evidence from larval chaetotaxy and morphology
- Creator:
- Michat, Mariano and Torres, Patricia L.M.
- Type:
- article, model:article, and TEXT
- Subject:
- Diving beetles, Dytiscidae, Hyphydrini, Pachydrus, larva, chaetotaxy, and phylogeny
- Language:
- English
- Description:
- Phylogenetic relationships within the diving-beetle subfamily Hydroporinae are not well understood. Some authors include the genus Pachydrus Sharp, 1882 in the tribe Hyphydrini, whereas others are in favour of excluding Pachydrus from the Hyphydrini and placing it in its own tribe, Pachydrini. Larval characters have been underutilised in phylogenetic studies, mainly because the larvae of many taxa within the family are unknown. In this study, the phylogenetic relationships of Pachydrus are studied based on a cladistic analysis of 34 taxa and 122 morphological larval characters. For this purpose, larvae of P. obesus Sharp, 1882 are described and illustrated in detail for the first time, with particular emphasis on morphometry and chaetotaxy. First and second instars for the genus were unknown. The results support a monophyletic origin of the tribe Hyphydrini excluding Pachydrus, based on four unique character states. On the other hand, Pachydrus is resolved as the sister group of the Hydrovatini. These results suggest Pachydrus should not be placed in the Hyphydrini. Given that the Hyphydrini minus Pachydrus is a distinctive clade, based on this study, it seems useful to recognise this group as Hyphydrini. Including Pachydrus in Hyphydrini would leave the tribe with a single larval apomorphy, as most characters present in the Hyphydrini and Pachydrus are also present in the Hydrovatini. However, in the absence of larvae of Heterhydrus Fairmaire, 1869 and of a more comprehensive and inclusive analysis, we do not propose a formal exclusion of Pachydrus from Hyphydrini at this stage. Pachydrus is a highly distinctive genus within the Hydroporinae and is characterised by several larval apomorphies.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public