Influence of preservative and mounting media on the size and shape of monogenean sclerites

Abstract

Based on Cichlidogyrus sp. (Monogenea, Ancyrocephalidae) specimens from Hemichromis sp. hosts, we tested the influence of different methods to fix/preserve samples/specimens [frozen material, alcohol or formalin preserved, museum process for fish preservation (fixed in formalin and preserved in alcohol)] and different media used to mount the slides [tap water, glycerin ammonium picrate (GAP), Hoyer's one (HM)] on the size/shape of sclerotized parts of monogenean specimens. The results show that the use of HM significantly increases the size of haptoral sclerites [marginal hooks I, II, IV, V, and VI; dorsal bar length, width, distance between auricles and auricle length, ventral bar length and width], and changes their shape [angle opening between shaft and guard (outer and inner roots) in both ventral and dorsal anchors, ventral bar much wider, dorsal one less curved]. This influence seems to be reduced when specimens/samples are fixed in formalin. The systematics of Monogenea being based on the size and shape of their sclerotized parts, to prevent misidentifications or description of invalid new species, we recommend the use of GAP as mounting medium; Hoyer's one should be restricted to monogenean specimens fixed for a long time which are more shrunken.

Four new species ofCichlidogyrus(Platyhelminthes, Monogenea, Dactylogyridae) from Lake Victoria haplochromine cichlid fishes, with the redescription ofC. bifurcatusandC. longipenis

“…5 ). The observed size differences may be due to two factors: 1) the mounting medium used when making the slides: Fankoua et al [7] demonstrated that the use of Hoyer’s increases the size and modifies the shape of sclerotized parts, and/or 2) the way Paperna & Thurston [35] made the drawings and took the measurements for the original description. Although measurements given in the original description are compatible with its drawings and scale bars ( Table 2 ), there are significant differences between these measurements and those we took from the type slide ( Table 2 ) (an exception is the ventral bar total length, which seems incomparable: we measured the length of a branch while the original authors probably measured the total length of the bar).…”

Parasitic flatworms infecting thorny skate,Amblyraja radiata:infection by the monogeneansAcanthocotyle verrilliandRajonchocotyle emarginatain Svalbard

“…Morphometric parameters where subsequently analysed by principal component analysis (PCA) in the R software package stats [35] and visualised using ggplot2 [36]. Only specimens mounted on slides with GAP were part of the analyses to avoid effects of the staining method on the results [37]. The following variables were used in PCA: (1) the ratios body width/total length (TL), (2) body length/TL, (3) pharynx length/TL, (4) pharynx width/TL, (5) diameter of the pseudohaptor/TL, (6) number of sclerite rows/TL, (7) testes maximum width/TL, (8) germarium length/TL and (9) germarium width/TL.…”

Interaksi Molekuler Amonium Hidroksida

“…Jika napas sulit, berikan oksigen. Dapatkan bantuan medis (96,(193)(194)(195)(196)(197)(198)(199)(200)(201)(202)(203)(204)(205)(206)(207)(208)(209)(210)(211) . Catatan dokter : Ssetelah paparan inhalasi, amati selama 24 s.d 72 jam sebagai edema paru mungkin tertunda…”