Displaying publications 1 - 20 of 79 in total

Abstract:
Sort:
  1. Sartiami D, Watson GW, M N MR, Hanifah Y M, A B I
    Zootaxa, 2015;3957(2):235-8.
    PMID: 26249070 DOI: 10.11646/zootaxa.3957.2.8
    Matched MeSH terms: Animal Structures/anatomy & histology
  2. Grismer LL, Ismail LH, Awang MT, Rizal SA, Ahmad AB
    Zootaxa, 2014;3821(4):457-64.
    PMID: 24989758 DOI: 10.11646/zootaxa.3821.4.4
    A new species of scincid lizard, Lipinia sekayuensis sp. nov. from Hutan Lipur Sekayu, Terengganu State in northeastern Peninsular Malaysia is most similar to L. surda (Boulenger) but differentiated from it and all other species of Lipinia by having the combination of an adult SVL of 42.3 mm; six supralabials; five infralabials; four supraoculars; prefrontals widely separated; two loreals; fused frontoparietals; lower eyelids bearing a large, transparent disc; 21 midbody scale rows; 56 paravertertebral scale rows; 65 ventral scale rows; enlarged, precloacal scales; 10 subdigital lamellae on the third finger; 11, 15, and seven lamellae on the third, fourth, and fifth toes, respectively; distal subdigital lamellae keeled; a median row of slightly enlarged, subcaudal scales present; a generally unicolor, dark-brown dorsum bearing nine very faint, diffuse, darker stripes; and an external ear opening replaced by a scaly, auditory depression.
    Matched MeSH terms: Animal Structures/anatomy & histology
  3. Aftab SMA, Ahmad KA
    PLoS One, 2017;12(8):e0183456.
    PMID: 28850622 DOI: 10.1371/journal.pone.0183456
    The Humpback whale tubercles have been studied for more than a decade. Tubercle Leading Edge (TLE) effectively reduces the separation bubble size and helps in delaying stall. They are very effective in case of low Reynolds number flows. The current Computational Fluid Dynamics (CFD) study is on NACA 4415 airfoil, at a Reynolds number 120,000. Two TLE shapes are tested on NACA 4415 airfoil. The tubercle designs implemented on the airfoil are sinusoidal and spherical. A parametric study is also carried out considering three amplitudes (0.025c, 0.05c and 0.075c), the wavelength (0.25c) is fixed. Structured mesh is utilized to generate grid and Transition SST turbulence model is used to capture the flow physics. Results clearly show spherical tubercles outperform sinusoidal tubercles. Furthermore experimental study considering spherical TLE is carried out at Reynolds number 200,000. The experimental results show that spherical TLE improve performance compared to clean airfoil.
    Matched MeSH terms: Animal Structures/anatomy & histology*
  4. Kittel RN, Austin AD
    Zootaxa, 2013;3694:486-92.
    PMID: 26312306
    The apparently rare chelonine wasp genus Wushenia Zettel was previously known only from a single species Wushenia nana Zettel, collected by Townes at 1150 m from Wushe, Taiwan in 1983. Here we describe a second species, Wushenia australiensis sp. nov. from coastal New South Wales, Australia. This second species extends the known distribution of the genus from the Oriental into the Australasian region, indicating either an extreme disjunct distribution or that Wushenia may also occur on the landmasses inbetween, e.g. the Philippines, Malaysia, Indonesia and/or Papua New Guinea. In addition to a detailed description of the new species, a re-diagnosis of the genus and type species, and a key to species are presented.
    Matched MeSH terms: Animal Structures/anatomy & histology
  5. Karin BR, Das I, Bauer AM
    Zootaxa, 2016 Mar 22;4093(3):407-23.
    PMID: 27394504 DOI: 10.11646/zootaxa.4093.3.7
    We describe two new species of skinks from Gunung Penrissen, Sarawak, Malaysia, in northern Borneo, Tytthoscincus batupanggah sp. nov. and T. leproauricularis sp. nov. Morphological and molecular analyses both corroborate the two new species as unique compared to all other Tytthoscincus and additional Sphenomorphus that are candidates for taxonomic placement in the genus Tytthoscincus. Despite their phenotypic similarity and sympatric distribution, a molecular analysis shows that the new species are not sister taxa and exhibit a deep genetic divergence between each of their respective sister taxa. We discuss how historical climatic and geographic processes may have led to the co-distribution of two relatively distantly related phenotypically similar species. In light of these discoveries, we also emphasize the importance of conserving primary montane tropical rainforest for maintaining species diversity.
    Matched MeSH terms: Animal Structures/anatomy & histology
  6. Bayer S
    Zootaxa, 2014;3826(1):1-54.
    PMID: 24990038 DOI: 10.11646/zootaxa.3826.1.1
    Seven new Psechrus species are described from South East Asia: P. arietinus sp. nov.(♂♀, Vietnam), P. insulanus sp. nov.(♂, Thailand), P. ampullaceus sp. nov.(♂♀, Vietnam), P. omistes sp. nov.(♂, Indonesia, Sumatra), P. quasillus sp. nov.(♂♀, Malaysia, Borneo), P. huberi sp. nov.(♀, Philippines), and P. wade sp. nov.(♂, Philippines). For the following species, new records are listed and intraspecific variation is discussed and illustrated: P. libelti Kulczyński, 1908, P. norops Bayer, 2012, P. rani Wang & Yin, 2001, P. khammouan Jäger, 2007, P. luangprabang Jäger, 2007, P. jaegeri Bayer, 2012, P. obtectus Bayer, 2012, P. kenting Yoshida, 2009 and P. crepido Bayer, 2012, and Fecenia protensa Thorell, 1891. The latter species is recorded from Vietnam for the first time. P. norops, P. libelti and an unidentified Psechrus species from Baluno, Mindanao are for the first time characterised and illustrated by their pre-epigynes and pre-vulvae.
    Matched MeSH terms: Animal Structures/anatomy & histology
  7. Benjamin SP
    Zootaxa, 2014;3894:177-82.
    PMID: 25544630 DOI: 10.11646/zootaxa.3894.1.15
    Two new species of Pharta, P. sudmannorum sp. nov. (♂♀, Borneo) and P. koponeni sp. nov. (♂, Thailand) are described. Furthermore, Ibana senagang gen. nov. & sp. nov. from Malaysia is described based on its exceptional palp, which has a reduced, movable conductor and thick-long spines on the distal, ventral surface of the tibia, reminiscent of Epidius Thorell, 1877.
    Matched MeSH terms: Animal Structures/anatomy & histology
  8. Bezděk J
    Zootaxa, 2016 Mar 04;4085(4):504-24.
    PMID: 27394316 DOI: 10.11646/zootaxa.4085.4.3
    The species of the genus Coeligetes Jacoby, 1884 distributed in Malaysia and Indonesia are revised, illustrated and keyed. New species, C. howardi sp. nov. from Borneo is described. New synonymy Coeligetes submetallica Jacoby, 1884 = C. wilcoxi Mohamedsaid, 1994 (syn. nov.) is proposed. New genus and species Coeligetoides trifurcatus gen. nov., sp. nov. (Malaysia, Brunei, Indonesia and Thailand) is described, illustrated and compared with related genera.
    Matched MeSH terms: Animal Structures/anatomy & histology
  9. Cabra-García J, Brescovit AD
    Zootaxa, 2016 Jan 27;4069(1):1-183.
    PMID: 27395905 DOI: 10.11646/zootaxa.4069.1.1
    A taxonomic revision and phylogenetic analysis of the spider genus Glenognatha Simon, 1887 is presented. This analysis is based on a data set including 24 Glenognatha species plus eight outgroups representing three related tetragnathine genera and one metaine as the root. These taxa were scored for 78 morphological characters. Parsimony was used as the optimality criterion and a sensitivity analysis was performed using different character weighting concavities. Seven unambiguous synapomorphies support the monophyly of Glenognatha. Some internal clades within the genus are well-supported and its relationships are discussed. Glenognatha as recovered includes 27 species, four of them only known from males. A species identification key and distribution maps are provided for all. New morphological data are also presented for thirteen previously described species. Glenognatha has a broad distribution occupying the Neartic, Afrotropic, Indo-Malaya, Oceania and Paleartic regions, but is more diverse in the Neotropics. The following eleven new species are described: G. vivianae n. sp., G. caaguara n. sp., G. boraceia n. sp. and G. timbira n. sp. from southeast Brazil, G. caparu n. sp., G. januari n. sp. and G. camisea n. sp. from the Amazonian region, G. mendezi n. sp., G. florezi n. sp. and G. patriceae n. sp. from northern Andes and G. gouldi n. sp. from Southern United States and central Mexico. Females of G. minuta Banks, 1898, G. gaujoni Simon, 1895 and G. gloriae (Petrunkevitch, 1930) and males of G. globosa (Petrunkevitch, 1925) and G. hirsutissima (Berland, 1935) are described for the first time. Three new combinations are proposed in congruence with the phylogenetic results: G. argyrostilba (O. P.-Cambridge, 1876) n. comb., G. dentata (Zhu & Wen, 1978) n. comb. and G. tangi (Zhu, Song & Zhang, 2003) n. comb., all previously included in Dyschiriognatha Simon, 1893. The following taxa are newly synonymized: Dyschiriognatha montana Simon, 1897, Glenognatha mira Bryant, 1945 and Glenognatha maelfaiti Baert, 1987 with Glenognatha argyrostilba (Pickard-Cambridge, 1876) and Glenognatha centralis Chamberlin, 1925 with Glenognatha minuta Banks, 1898.
    Matched MeSH terms: Animal Structures/anatomy & histology
  10. Chan KO, Grismer LL, Brown RM
    Zootaxa, 2014;3900(4):569-80.
    PMID: 25543757 DOI: 10.11646/zootaxa.3900.4.7
    A new species of Narrow-mouthed frog of the genus Kaloula is described from northern Peninsular Malaysia. Kaloula latidisca sp. nov. is genetically and morphologically most similar to K. baleata and K. indochinensis but differs from those and other congeners by the unique combination of the following characters: (1) adult males SVL 49.2-56.2 mm (x̅=53.5 ± 3.0; N=4); (2) finger tips expanded into large, transversely expanded discs (disc width 2.8-3.1 mm, x̅=3.0 ± 0.1); (3) inner metatarsal tubercle large, oval, distinctly raised, slightly shorter than first toe; (4) three subarticular tubercles on fourth toe; (5) toe webbing formula: I 1-2 II 1-3 III 2-3.5 IV 4-2 V; and (6) yellow to orange irregularly shaped patch on the axillary, inguinal and posterior region of thigh.
    Matched MeSH terms: Animal Structures/anatomy & histology
  11. Colloff MJ, Cameron SL
    Zootaxa, 2014;3780:263-81.
    PMID: 24871836 DOI: 10.11646/zootaxa.3780.2.3
    The genus Austronothrus was previously known from three species recorded only from New Zealand. Austronothrus kinabalu sp. nov. is described from Sabah, Borneo and A. rostralis sp. nov. from Norfolk Island, south-west Pacific. A key to Austronothrus is included. These new species extend the distribution of Austronothrus beyond New Zealand and confirms that the subfamily Crotoniinae is not confined to former Gondwanan landmasses. The distribution pattern of Austronothrus spp., combining Oriental and Gondwanan localities, is indicative of a curved, linear track; consistent with the accretion of island arcs and volcanic terranes around the plate margins of the Pacific Ocean, with older taxa persisting on younger island though localised dispersal within island arc metapopulations. Phylogenetic analysis and an area cladogram are consistent with a broad ancestral distribution of Austronothrus in the Oriental region and on Gondwanan terranes, with subsequent divergence and distribution southward from the Sunda region to New Zealand. This pattern is more complex than might be expected if the New Zealand oribatid fauna was derived from dispersal following re-emergence of land after inundation during the Oligocene (25 mya), as well as if the fauna emanated from endemic, relictual taxa following separation of New Zealand from Gondwana during the Cretaceous (80 mya).
    Matched MeSH terms: Animal Structures/anatomy & histology
  12. Seah YG, Hanafi N, Mazlan AG, Chao NL
    Zootaxa, 2015;3956(2):271-80.
    PMID: 26248918 DOI: 10.11646/zootaxa.3956.2.7
    A new species of Larimichthys from Terengganu, east coast of Peninsular Malaysia is described from specimens collected from the fish landing port at Pulau Kambing, Kuala Terengganu. Larimichthys terengganui can be readily distinguished from other species of the genus by having an equally short pair of ventral limbs at the end of the gas bladder appendages, which do not extend lateral-ventrally to the lower half of the body wall, and fewer dorsal soft rays (29-32 vs. 31-36) and vertebrae (24 vs. 25-28). Larimichthys terengganui can be distinguished from L. polyactis and L. crocea by having a gill raker at the angle of first gill arch shorter than the gill filament. Furthermore, the second anal spine in L. terengganui is equal or slightly shorter than eye diameter (vs. shorter in L. polyactis); L. terengganui has 8-9 anal soft rays (vs. only 7 in L. pamoides). Snout length of L. terengganui is greater than eye diameter, whereas in L. crocea the snout is shorter than eye diameter. A key to species of Larimichthys is provided. All obtained specimens of the species were recorded from Terengganu waters, east coast of Peninsular Malaysia.
    Matched MeSH terms: Animal Structures/anatomy & histology
  13. Takaoka H, Srisuka W, Saeung A, Otsuka Y, Choochote W
    Zootaxa, 2013;3694:280-8.
    PMID: 26312290
    Simulium (Nevermannia) khunklangense sp. nov. is described from females, males, pupae and larvae collected in Doi Inthanon National Park, Chiang Mai, Thailand. This new species is placed in the vernum species-group of the subgenus Nevermannia and is similar to S. (N.) chomthongense Takaoka & Srisuka described from Doi Inthanon National Park, Thailand, but is distinguished in the male by the number of enlarged upper-eye facets and the relative width of the hind basitarsus against the hind tibia and femur, and in the pupa by the short common basal stalk of the gill and the cocoon with an anterodorsal bulge or a short anterodorsal projection. Taxonomic notes are provided to separate this new species from five other known species of the vernum species-group, which share an accessory sclerite on the larval abdomen, a rare characteristics in this species-group.
    Matched MeSH terms: Animal Structures/anatomy & histology
  14. Grismer LL, Quah ES, Wood PL, Anuar S, Muin A, Davis HR, et al.
    Zootaxa, 2016 Jul 07;4136(3):461-90.
    PMID: 27395729 DOI: 10.11646/zootaxa.4136.3.3
    An integrative taxonomic analysis is used to delimit and describe three new species of Pseudocalotoes from the sky island archipelago of the Banjaran (=mountain range) Titiwangsa of Peninsular Malaysia. Pseudocalotes drogon sp. nov., from Fraser's Hill, Pahang is basal to the sister species P. larutensis from Bukit Larut, Perak in the Banjaran Bintang and the new species P. rhaegal sp. nov. from Cameron Highlands, Pahang. Pseudocalotes drogon sp. nov. is differentiated from all other species of Psuedocalotes by having the combination of a flat rostrum; seven postrostrals; an interparietal; 11 circumorbitals; five canthals; 7-10 superciliaries; one scale between the rostral and nasal; nine supralabials; eight infralabials; 10 postnasal-suborbital scales; four postmentals; five or six sublabials; five or six chinshields; 47 smooth, wide, gular scales; weak transverse gular and antehumeral folds; two enlarged scales between the ear and eye; enlarged upper and lower posttemporals; a single enlarged supratympanic; no enlarged postrictals; three large scales bordering the dorsal margin of the ear opening; large pretympanic scales; eight scales in the nuchal crest not separated by a gap; enlarged vertebral scales extending to the tip of the tail; keeled and non-plate-like scales on flanks; 51 midbody scales; midventrals smaller than dorsals; 19 subdigital lamellae on the fourth finger; 23 subdigital lamellae on the fourth toe; preaxial scales on third toe enlarged and spinose; subdigital lamellae not unicarinate; HW/HL 0.52; HL/SVL 0.31; no elbow or knee patches; and a male dewlap color of lime-green bearing a central yellow spot. Pseudocalotes rhaegal sp. nov. is differentiated from all other Psuedocalotes by having the combination of a convex rostrum; 6-8 postrostrals; an interparietal; nine or 10 circumorbitals; five canthals; 7-10 superciliaries; one or two scales between the rostral and nasal scales; eight or nine supralabials; seven or eight infralabials; 11 or 12 postnasal-suborbital scales; four postmentals; four or five chinshields; 40-45 smooth, wide, gular scales; no transverse gular fold; a weak antehumeral fold; three or four enlarged scales between the ear and eye; an enlarged upper and lower posttemporal; an enlarged supratympanic; no enlarged postrictals; no large scales bordering the upper margin of the ear opening or in the pretympanic region; 6-8 enlarged nuchal crest scales not separated by a gap; enlarged vertebral scales extending to the base of the tail; weakly keeled, non-plate-like scales on the flanks; 52-58 midbody scales; midventrals smaller than dorsals; 19-21 subdigital lamellae on the fourth finger; 22-26 subdigital lamellae on the fourth toe; preaxial scales on the third enlarged and rounded; subdigital lamellae not unicarinate; HW/HL 0.50-0.54; HL/SVL 0.28-0.30; no elbow or knee patches; and female dewlap color yellow bearing a purple base. The analyses also indicated that the new species, P. viserion sp. nov. from Genting Highlands, Pahang in the southern section of the Banjaran Titiwangsa is the sister species of P. flavigula from Cameron Highlands 121 km to the north and can be separated from all other species of Psuedocalotes by having the combination of three postrostrals; 10 circumorbitals; four or five canthals; 5-7 superciliaries; rostral and nasals in contact; supralabials contacting the nasal; six or seven supralabials; six or seven infralabials; two or three postmentals; 47 or 48 smooth, flat, gular scales; three chinshields; weak transverse gular and antehumeral folds; two enlarged scales between the ear and eye; an enlarged upper and lower posttemporal; an enlarged supratympanic; no enlarged postrictals; 7-9 nuchal crest scales lacking gaps and not extending beyond midbody; weakly keeled and plate-like scales on the flanks; 35-38 midbody scales; ventrals smaller than dorsals; 22 or 23 subdigital lamellae on the fourth finger; 26 or 27 subdigital lamellae on the fourth toe; preaxial scales on the third toe not modified; subdigital scales not unicarinate; HW/HL 0.62; no white marking below the eye; dewlap in males yellow; and no elbow or knee patches. Pseudocalotes rhaegal sp. nov. most likely occurs in syntopy with P. flavigula in Tanah Rata at Cameron Highlands and its discovery adds to a growing body of literature detailing the recent descriptions of several new, upland, closely related, sympatric species in Peninsular Malaysia. Another new population referred to here as Pseudocalotes sp. nov. from the Hala-Bala Wildlife Sanctuary, Betong District, Yala Province, Thailand is discussed. The discovery and description of these three new Pseudocalotes from the upland regions of Peninsular Malaysia continues to underscore the remarkably high herpetological diversity and ecological complexity in this sky island archipelago that is still underestimated, unappreciated, and unprotected.
    Matched MeSH terms: Animal Structures/anatomy & histology
  15. Yeates DK, Cranston PS
    Zootaxa, 2013;3680:1-211.
    PMID: 26146692 DOI: 10.11646/zootaxa.3680.1.1
    Donald Henry Colless (24 August 1922–16 February 2012) was a taxonomist at the Australian National Insect Collection (ANIC) from 1960 until his retirement in 1987. He continued working in ANIC as an Honorary Fellow until his death in 2012. Don’s main scientific interests were in the taxonomy and biology of true flies, and in the theory of phylogenetic reconstruction and classification. Don was trained in entomology at the University of Sydney, and spent nearly two decades of his early career in Asia studying mosquitoes and disease transmission, first in the Army during the Second World War in New Guinea and Borneo (1942–45), then after the war in North Borneo (1947–1952) and as a lecturer in the Department of Parasitology at the University of Malaya (1952–1960) in Singapore. We list the 127 scientific papers and book chapters that Don published during his scientific career that spanned 64 years. Six of these papers were published in the prestigious international journal Nature, and he was Chief Curator of the ANIC from 1971–1977. Don had extremely broad taxonomic interests, publishing on the taxonomy of 18 families of Diptera that spanned the phylogenetic breadth of the order. He described as new to science the fly families Perissommatidae and Axiniidae, thirteen new genera and over 120 species and, with David McAlpine, authored the Diptera chapters in both editions of The Insects of Australia (Melbourne University Press, 1970 and 1991). He published a number of influential critiques of cladistic theory in the 1960's and 1970's, and advocated a phenetic approach to the discovery of taxonomic groups, and phylogenetic reconstruction.
    Matched MeSH terms: Animal Structures/anatomy & histology
  16. Cranston PS
    Zootaxa, 2016 May 09;4109(3):315-31.
    PMID: 27394867 DOI: 10.11646/zootaxa.4109.3.3
    The presence of the Afro-Australian genus Conochironomus Freeman, 1961 (Diptera: Chironomidae) in Asia has been recognised only informally. An unpublished thesis included Conochironomus from Singapore, and the genus has been keyed from Malaysia without named species. Here, the Sumatran Conochironomus tobaterdecimus (Kikuchi & Sasa, 1980) comb. n. is recorded from Singapore and Thailand. The species is transferred from Sumatendipes Kikuchi & Sasa, 1980, rendering the latter a junior synonym (syn. n.) of Conochironomus Freeman. Conochironomus nuengthai sp. n. and Conochironomus sawngthai sp. n. are described as new to science, based on adult males from Chiang Mai, Thailand. All species conform to existing generic diagnoses for all life stages, with features from male and female genitalia, pupal cephalic tubercles and posterolateral 'spurs' of tergite VIII providing evidence for species distinction. Some larvae are linked to C. tobaterdecimus through molecular barcoding. Variation in other larvae, which clearly belong to Conochironomus and are common throughout Thailand, means that they cannot be segregated to species. Larval habitats include pools in river beds, urban storage reservoirs, drains with moderately high nutrient loadings, and peat swamps. Endochironomus effusus Dutta, 1994 from north-eastern India may be a congener but may differ in adult morphology, thereby precluding formal new combination until discrepancies can be reconciled. Many problems with vouchering taxonomic and molecular material are identified that need to be rectified in the future.
    Matched MeSH terms: Animal Structures/anatomy & histology
  17. Schilthuizen M, Scott BJ, Cabanban AS, Craze PG
    Heredity (Edinb), 2005 Sep;95(3):216-20.
    PMID: 16077741
    Tree snails of the subgenus Amphidromus s. str. are unusual because of the chiral dimorphism that exists in many species, with clockwise (dextrally) and counter-clockwise (sinistrally) coiled individuals co-occurring in the same population. Given that mating in snails is normally impeded when the two partners have opposite coil, positive frequency-dependent selection should prevent such dimorphism from persisting. We test the hypothesis that a strong population structure with little movement between tree-based demes may result in the fixation of coiling morphs at a very small spatial scale, but apparent dimorphism at all larger scales. To do so, we describe the spatial structure in a Malaysian population of A. inversus (Müller, 1774) with 36% dextrals. We marked almost 700 juvenile and adult snails in a piece of forest consisting of 92 separate trees, and recorded dispersal and the proportions of dextrals and sinistrals in all trees over a 7-day period. We observed frequent movement between trees (155 events), and found that no trees had snail populations with proportions of dextrals and sinistrals that were significantly different from random. Upon recapture 1 year later, almost two-thirds of the snails had moved away from their original tree. We conclude that population structure alone cannot stabilise the coil dimorphism in Amphidromus.
    Matched MeSH terms: Animal Structures/anatomy & histology*
  18. Bell AJ, Cryan JR
    Zootaxa, 2013;3640:57-69.
    PMID: 26000404
    Two new monotypic spittlebug genera and their type species in the family Machaerotidae, subfamily Enderleiniinae, are described and illustrated: Labramachaerota korupa gen. & sp. n. (with type locality in Cameroon) and Kyphomachaerota maaia gen. & sp. n. (with type locality in Sarawak, Malaysia).
    Matched MeSH terms: Animal Structures/anatomy & histology
  19. Hertwig ST, Min PY, Haas A, Das I
    Zootaxa, 2014.
    PMID: 24943439 DOI: 10.11646/zootaxa.3814.3.9
    A new species of stream toad of the genus Ansonia is described from Gunung Murud, Pulong Tau National Park, of northern Sarawak, Malaysia, Borneo. Ansonia vidua, sp. nov., is morphologically distinguished from its Bornean congeners by the following combination of characters: medium size (SVL of adult females 33.5-34.4 mm); body uniformly black-brown in life; absence of a visible pattern on dorsum or limbs; presence of two low interorbital ridges; shagreened skin on dorsum, sides and upper surfaces of the limbs with numerous homogeneously small, rounded warts; first finger shorter than second; reduced webbing between the toes and an absence of a sharp tarsal ridge. Uncorrected genetic distances between related taxa of > 4.3% in 16S rRNA gene support its status as a hitherto undescribed species.
    Matched MeSH terms: Animal Structures/anatomy & histology
  20. Schilthuizen M, Davison A
    Naturwissenschaften, 2005 Nov;92(11):504-15.
    PMID: 16217668
    The direction that a snail (Mollusca: Gastropoda) coils, whether dextral (right-handed) or sinistral (left-handed), originates in early development but is most easily observed in the shell form of the adult. Here, we review recent progress in understanding snail chirality from genetic, developmental and ecological perspectives. In the few species that have been characterized, chirality is determined by a single genetic locus with delayed inheritance, which means that the genotype is expressed in the mother's offspring. Although research lags behind the studies of asymmetry in the mouse and nematode, attempts to isolate the loci involved in snail chirality have begun, with the final aim of understanding how the axis of left-right asymmetry is established. In nature, most snail taxa (>90%) are dextral, but sinistrality is known from mutant individuals, populations within dextral species, entirely sinistral species, genera and even families. Ordinarily, it is expected that strong frequency-dependent selection should act against the establishment of new chiral types because the chiral minority have difficulty finding a suitable mating partner (their genitalia are on the 'wrong' side). Mixed populations should therefore not persist. Intriguingly, however, a very few land snail species, notably the subgenus Amphidromus sensu stricto, not only appear to mate randomly between different chiral types, but also have a stable, within-population chiral dimorphism, which suggests the involvement of a balancing factor. At the other end of the spectrum, in many species, different chiral types are unable to mate and so could be reproductively isolated from one another. However, while empirical data, models and simulations have indicated that chiral reversal must sometimes occur, it is rarely likely to lead to so-called 'single-gene' speciation. Nevertheless, chiral reversal could still be a contributing factor to speciation (or to divergence after speciation) when reproductive character displacement is involved. Understanding the establishment of chirality, the preponderance of dextral species and the rare instances of stable dimorphism is an important target for future research. Since the genetics of chirality have been studied in only a few pulmonate species, we also urge that more taxa, especially those from the sea, should be investigated.
    Matched MeSH terms: Animal Structures/anatomy & histology*
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links