The order Gobiiformes is made up of more than 2200 species,representing one of the most diverse groups among teleost fishes.The biological causes for the tachytelic karyotype evolution of the gobies have not yet been fully studied.Here we expanded cytogenetic data for the Eleotridae family,analyzing the neotropical species Dormitator maculatus,Eleotris pisonis,Erotelis smaragdus,and Guavina guavina.In addition,a meta-analytical approach was followed for elucidating the karyotype diversification versus biological aspects(habitat and egg type)of the Gobiiformes.The species E.smaragdus and E.pisonis present 2n=46 acrocentric chromosomes(NF=46),D.maculatus 2n=46(36sm+4st+6a;NF=86),and G.guavina,the most divergent karyotype,with 2n=52 acrocentric chromosomes(NF=52).Besides numeric and structural diversification in the karyotypes,the mapping of rDNAs and microsatellites also showed noticeable numerical and positional variation,supporting the high chromosomal evolutionary dynamism of these species.In Gobiiformes,karyotype patterns which are more divergent from the basal karyotype(2n=46a)are associated with characteristics less effective to dispersion,such as the benthic habit.These adaptive characteristics,connected with the organization of the repetitive DNA content in the chromosomes,likely play a synergistic role in the remarkable karyotype diversification of this group.
Simião Alefe Soares da SilvaPaulo Augusto de Lima-FilhoClóvis Coutinho da Motta-NetoGideão Wagner Werneck Félix da CostaMarcelo de Bello CioffiLuiz Antônio Carlos BertolloWagner Franco Molina
The pufferfish Lagocephalus sceleratus is an invasive Lessepsian species of Indo-Pacific origin that has established an increasing population over the past decade in the Levantine basin of the Mediterranean. Besides its toxicity due to the accumulation of tetrodotoxin in its body, it is causing damage to fishing gears and fishermen＇s catches. This study aims to provide data on the population structure and sexual maturity of this species in the eastern basin of the Mediterranean. A total of 214 individuals were collected in the coastal marine waters of Lebanon and Syria, between January 2012 and June 2013 by means of different types of nets and lines, on soft bottoms, at depths ranging from 10 m to 170 m. The TL （total length） of the samples varies between 10.8 cm and 71 cm. The most common size classes, represented by 125 individuals, are the ones between 30 cm and 50 cm TL, with a bulge at 40 cm, represented by 44 individuals. The average TL is 43.99 cm （standard deviation： SD = 17.65） for both males and females. The TW （total weight） of the specimens ranges between 14 g and 4,603 g with an average value of 1,458.52 g （SD = 1,329.49）. The sex ratio （M/F） is 1：1.35 with a total number of 87 males, 118 females and nine unidentified individuals. The weight-length relationship （TW = aTLb） shows a negative allometric growth with b = 2.9481 and R2 = 0.9806. The condition factor （K） is close to one for all samples. The average value of the GSI （gonadosomatic index） shows a substantial increase from winter to spring. The spawning takes place between April and June.
Cranial morphological features of the stem-group sarcopterygian Guiyu oneiros Zhu et al.,2009 provided here include the dermal bone pattern and anatomical details of the ethmosphenoid.Based on those features,we restored,for the first time,the skull roof bone pattern in the Guiyu clade that comprises Psarolepis and Achoania.Comparisons with Onychodus,Achoania,coelacanths,and actinopterygians show that the posterior nostril enclosed by the preorbital or the preorbital process is shared by actinopterygians and sarcopterygians,and the lachrymals in sarcopterygians and actinopterygians are not homologous.The endocranium closely resembles that of Psarolepis,Achoania and Onychodus;however,the attachment area of the vomer possesses irregular ridges and grooves as in Youngolepis and Diabolepis.The orbito-nasal canal is positioned mesial to the nasal capsule as in Youngolepis and porolepiforms.The position of the hypophysial canal at the same level or slightly anterior to the ethmoid articulation represents a synapmorphy of the Guiyu clade.The large attachment area of the basicranial muscle indicates the presence of a well-developed intracranial joint in Guiyu.
Two complete specimens from the Pelsonian （Middle Anisian, Middle Triassic） of Luoping, Yunnan Province, South China are referred to a new actinopterygian genus, Luopingichthys gen. nov., and ascribed to the perleidiform family Polzbergidae based especially on a typical synapomorphy of a peculiar premaxillary-maxillary complex, i.e., the fusion between premaxillary and maxillary along the antero-dorsal margin of the maxillary. The new taxon differs from other deep-bodied representatives of the family, Felberia and Stoppania, in its fusiform or deep fusiform body shape; sickle-shaped preopercular with short infraorbital process; lack of modified scales at the base of the anal fin; the short-based dorsal fin; scarcely ornamented scales; and thin anterior teeth. Based on a redescription of the holotype of the taxon Ctenognathichthys hattichi from the Middle Triassic （Ladinian） Prosanto Formation, Canton Graubiinden, eastern Switzerland, the only known specimen, which shows the same fusion between premaxillary and maxillary, the systematic position of the species is clarified and the taxon is proposed to be a further representative of the family Polzbergidae, and is transferred to the new genus.
SUN ZuoyuAndrea TINTORIJIANG DayongCristina LOMBARDOMarco RUSCONIHAO WeichengSUN Yuanlin
