Reproductive biology of the introduced sailfin catfish Pterygoplichthys pardalis (Pisces: Loricariidae) in peninsular Malaysia

Reproductive biology of the introduced sailfin cat fish Pterygoplichthys pardalis in the Langat River of peninsular Malaysia was studied. Fish samples were collected monthly from Langat River during March 2003-June 2004. The sex ratio observed for P. pardalis was female-biased with 1: 2. Gonadal maturity stage is achieved at 12.5 cm standard length (SL) for males and 13.0 cm SL for females. This species appeared to have continuous spawning that peaked when water levels were high between September and January. Egg sizes were found to reach as large as 3.3 mm in dia in the ovary; suggesting that they spawn in batches. Fecundity varied from 1297 to 18791 numbers per brood, proportional to individual size. Data obtained from this study indicate that the introduced sailfin cat fish has successfully colonised in Langat River in Malaysia

Evidence of a J/ψΛJ/\psi\Lambda structure and observation of excited Ξ−\Xi^- states in the Ξb−→J/ψΛK−\Xi^-_b \to J/\psi\Lambda K^- decay

First evidence of a structure in the $J/\psi{\Lambda}$ invariant mass distribution is obtained from an amplitude analysis of $\Xi_b^-{\rightarrow}J/\psi{\Lambda}K^-$ decays. The observed structure is consistent with being due to a charmonium pentaquark with strangeness with a significance of $3.1\sigma$ including systematic uncertainties and look-elsewhere effect. Its mass and width are determined to be $4458.8\pm2.9^{+4.7}_{-1.1}$ MeV and $17.3\pm6.5^{+8.0}_{-5.7}$ MeV, respectively, where the quoted uncertainties are statistical and systematic. The structure is also consistent with being due to two resonances. In addition, the narrow excited $\Xi^-$ states, $\Xi(1690)^-$ and $\Xi(1820)^-$, are seen for the first time in a $\Xi^-_b$ decay, and their masses and widths are measured with improved precision. The analysis is performed using $pp$ collision data corresponding to a total integrated luminosity of 9 fb$^{-1}$, collected with the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV