STRONG GENETIC DIVERGENCE AMONG POPULATIONS OF A MARINE FISH WITH LIMITED DISPERSAL, ACANTHOCHROMIS POLYACANTHUS, WITHIN THE GREAT BARRIER REEF AND THE CORAL SEA

Abstract Acanthochromis polyacanthus is an unusual tropical marine damselfish that uniquely lacks pelagic larvae and has lost the capacity for broad‐scale dispersal among coral reefs. On the modern Great Barrier Reef (GBR), three color morphs meet and hydridize at two zones of secondary contact. Allozyme electrophoreses revealed strong differences between morphs from the southern zone but few differences between morphs from the northern counterpart, thus suggesting different contact histories. We explore the phylogeography of Acanthochromis polyacanthus with mitochondrial cytochrome b region sequences (alignment of 565 positions) obtained from 126 individuals representing seven to 12 fish from 13 sites distributed over 12 reefs of the GBR and the Coral Sea. The samples revealed three major clades: (1) black fish collected from the southern GBR; (2) bicolored fish collected from the GBR and one reef (Osprey) from the northern Coral Sea; (3) black and white monomorphs collected from six reefs in the Coral Sea. All three clades were well supported (72–100%) by bootstrap analyses. Sequence divergences were very high between the major clades (mean = 7.6%) as well as within them (2.0–3.6%). Within clades, most reefs segregated as monophyletic assemblages. This was revealed both by phylogenetic analyses and AMOVAs that showed that 72–90% of the variance originated from differences among groups, whereas only 5–13% originated within populations. These patterns are discussed in relation to the known geological history of coral reefs of the GBR and the Coral Sea. Finally, we ask whether the monospecific status of Acanthochromis should be revisited because the sequence divergences found among our samples is substantially greater than those recorded among well‐recognized species in other reef fishes.     

EVALUATING KINSHIP OF NEWLY SETTLED JUVENILES WITHIN SOCIAL GROUPS OF THE CORAL REEF FISH ANTHIAS SQUAMIPINNIS

It is conventionally assumed that eggs and/or larvae of most coral reef fishes are thoroughly mixed during a pelagic phase, so that juvenile recruits at any particular reef site represent a random sample of the reproductive products entering the local gene pool. However, a recent review of biological factors that might limit mixing raised the testable hypothesis that groups of genetically related individuals may sometimes persist through the pelagic phase and settle as sibling cohorts (Shapiro, 1983). Here we provide a critical genetic test of this hypothesis by examining allozyme variation in juvenile aggregations of the serranid reef fish, Anthias squamipinnis. Results demonstrate that juvenile cohorts within large social groups in Anthias are not composed exclusively or predominantly of siblings, but rather represent a random sample of progeny from many matings. Also included are considerations of allelic and genotypic criteria by which hypotheses about sibling assemblages might generally be evaluated.     

THE BREEDING OF THE GREATER FLAMINGO AND GREAT WHITE PELICAN IN EAST AFRICA

This paper brings together observations on the breeding of the Greater Flamingo Phoenicopterus ruber and Great White Pelican Pelecanus onocrotalus, mainly at Lake Elmenteita, Kenya, 1951–1971. The Greater Flamingo bred at Lakes Elmenteita and Nakuru in 11/21 observed years and at Lakes Natron and Magadi in 5/12 observed years. On average, it breeds about every second year, but a succession of breeding years is followed by several years in which no breeding occurs. A history of 21 years' breeding at Lakes Nakuru and Elmenteita is given. At Elmenteita three sites have been used, the main site in every breeding year, the others less often. The number of pairs breeding in any year has varied from 500–9,250, but in 1968 flamingos bred three times, involving perhaps 8,500 pairs which made about 15,700 nests, some pairs perhaps laying twice or even thrice in a year. Losses of eggs (38.2% overall) were caused by rising water (16.2%), competition for nest space with Great White Pelicans (6.9%, after 1968 only), human interference (3.5%), Marabou Stork predation (1.8%) and other natural causes (9.8%). Losses among chicks totalled 68.3% overall and were mainly due to Marabou Storks (36.5%), undiagnosed disease (8.6%), and rising water (6.6%). Disease caused serious loss only in 1966, and after 1968 losses from Marabous rose from 2.7% to 76.5%, resulting in an increase in overall mortality from 48.7 to 92%. This was perhaps associated with the establishment of a fish factory at Lake Naivasha. When attacking flamingo colonies Marabous did not actually eat many eggs or chicks, but simply caused wholesale desertion by alarming the flamingos. In 1968 total desertion of a colony of 4,500 pairs was caused between 18 and 26 March by a maximum of 17 Marabous, and similar wholesale desertion was caused in later years. The overall breeding success among Greater Flamingos at Elmenteita was about 19% of eggs laid, but without the excessive post-1968 Marabou predation would have been about 30%. At such a rate Greater Flamingos require at least 24 years of adult life to replace themselves, but if the mortality caused by Marabous since 1968 continues they will require about 58 years, and the population will inevitably decline. Breeding success at Lakes Magadi and Natron has been higher, about 44% of eggs laid; but figures available are much more approximate than at Elmenteita. Some new data on display, nest-site selection, laying dates, clutch-size, hatching and creche behaviour are given for the Greater Flamingo. The Great White Pelican bred at Lake Elmenteita from 1968 to 1971 without a break, some birds laying in every month, but with reduced laying November–December. They bred on the same islands as, and in association with the Greater Flamingo, and caused heavy losses among the latter, not through aggressiveness, but simply because of their superior size and weight. Although food supply must ultimately have controlled the pelican's ability to breed, an adequate food supply was available for 6 years before they did and continued after they had ceased. Their breeding was finally triggered by the Greater Flamingo colonies, with which the pelicans associated. When a flamingo colony was deserted because of Marabou Storks the pelicans, unafraid themselves of the Marabous, also deserted. They also associated with, and wiped out, a colony of Sacred Ibis. From July 1968 to June 1969 about 2,600 pairs of pelicans bred at Elmenteita, rearing about 2,200 young to the flying stage. The breeding colony apparently comprised most of the adults from Lake Nakuru and Lake Naivasha, the main feeding areas. From July 1968 to January 1971 certainly 7,200 and probably 8,000 pairs of pelicans bred at Elmenteita. Some pairs may have bred twice or thrice in this period. Breeding ceased suddenly in January 1971, eggs, and small and large young being alike abandoned for no established reason, although food supply was certainly still plentiful. Additional information on pair formation, incubation and fledging periods, nest-relief, etc. is given. The best available record of the incubation period is 35–36 days. Nest relief takes place on average about once every 48 hrs, and is dependent on thermal activity enabling the pelicans to soar. At Elmenteita large young ate quantities of putrefying matter, including the corpses of other young pelicans. They also ate living young hatching from eggs, and up to 14 days old. Touch probably plays an important part in helping them to locate possible food in opaque water.     

LAKE RUDOLF AND THE PALAEARCTIC EXODUS FROM EAST AFRICA

The 165 000 km² sub-desert corridor in which Lake Rudolf lies may affect the routes taken by Palaearctic migrants in eastern Africa. A five-week study was made at Lake Rudolf during the spring migration period. The area is important for water birds, especially waders. It is less important for land birds, although on passage several passerines occur abundantly on Central Island, and some commonly in similarly well vegetated area (Turkwel river, littoral reedbeds). Some may fatten there before emigrating. Evidently the sub-desert corridor is not so inhospitable that it is entirely avoided or overflown by migrants.     

THE EFFECT OF WATER QUALITY ON OVIPOSITION IN BIOMPHALARIA GLABRATA (SAY, 1818) (PLANORBIDAE), AND A DESCRIPTION OF THE STAGES OF THE EGG-LAYING PROCESS

With the overall goal of developing a method to reliably induceovipositionin the freshwater pulmonate Biomphalariaglabrata, the effectsof water quality on female reproductivephysiology were examined.Groups of snails were subjected tocontrolled experimental conditionsconsisting of a daily regimen offeeding and water change. Aftera period of acclimatiz-ation, egg mass(EM) output under theseconditions was relatively stable, and snailslaid a majority(82.5%) of their EM during the initial 4 h followingdaily waterchange. When this regimen was perturbed by halting waterchangefor 24 h (dirty-water treatment), EM output was significantlyinhibited.When water change was resumed, EM output returned topreviouslevels within 4 h post-water change (PWC). This dirty-watertreatmentfollowed by water change also resulted in a significantincreasein mean EM size during the 4 h PWC when compared tocontrols.To better describe the events preceding egg-laying inB. glabrata,we then used these experimental manipulations toinduce ovipositionin groups of snails, and dissected them during the4 h followingwater change. Observations of the reproductive tracts ofstimulatedsnails allowed us to divide the egg-laying process, fromovulationto oviposition, into discrete stages, after de Jong-Brink,Koop,Roos & Bergamin-Sassen (1982). Stage I was characterized bythepresence of ova in the hermaphroditic duct and carrefour,andfertilized, packaged eggs in the oviduct and muciparousgland. StageII was characterized by the presence of packagedeggs in the othecalgland embedded in a mucous layer, constitutingthe egg mass to be laidon the substratum. No packaging eventswere occurring in thecarrefour/albumen gland region duringthis stage. When snails weredissected immediately after oviposition(Stage III), unpackaged ovawere observed in the hermaphroditicduct, carrefour, and oviduct. Themean time it took for snailsto reach Stage III was 120 6 49 min (SD),and this value wasstatistically different from the mean time toStages I and II,showing that our induction protocol results in atemporal progressionthrough the egg- laying process. Gonadal oocytedensity (oocytes/mm²of ovotestis) was quantified as afunction of these stages ofthe reproductive cycle, and was found tobe significantly lowerduring Stage II (fully formed egg mass inothecal gland) thanall other stages examined. Taken together, theseresults showthat female reproductive activity can be experimentallycontrolledthrough the manipulation of water quality, and that such aprotocolis a valuable tool for addressing specific questionsregardingthe reproductive physiology of B. glabrata. Theimplicationsof these results as they pertain to the regulation offemalereproductive activity in B. glabrata are discussed. (Received 15 January 1999; accepted 17 May 1999)     

脊髓灰质炎病毒重组体的构建及其抗原性状分析

以脊髓灰质炎病毒（以下简称脊灰病毒）为载体构建的重组体活病毒可以做为探讨脊灰病毒的抗原结构和特性的有益手段。在构建重组有甲型肝炎病毒小片段抗原多肽的重组脊灰病毒基础上,分析了脊灰病毒VP1上中和抗原位点I的空间构象特点,并探讨了插入的外源抗原片段对其空间结构的可能影响。     

贵州独山泥盆纪生物地层以及珊瑚的四次灭绝事件的研究

贵州省独山县县城附近的泥盆纪浅海相地层发育良好,底栖生物化石丰富,研究历史悠久,是我国南方浅海相泥盆系的标准剖面之一。文章从珊瑚化石的角度进行生物地层和群落生态的分析,并建立独山中、晚泥盆世7个珊瑚组合。文章最后还着重阐述独山泥盆纪珊瑚的4次灭绝事件：1)mid-Eifelian event(发生在龙洞水段之顶);2)late-Givetian event(发生在鸡窝寨段之顶);3)F-Fevent(发生在靠近尧梭组之底);4)D-Cevent(发生在革老河组之顶)。其中,F-F大灭绝事件对珊瑚群的影响最大。     

NIGHT COUNTS OF HARES AND OTHER ANIMALS IN EAST AFRICA

Night counts of hares and other animals were made on a disused airstrip in the Queen Elizabeth National Park, Uganda and on the road between Magadi and Nairobi in Kenya. Lepus crawshayi is the only species of hare which occurs in the Queen Elizabeth Park but L. capensis is also found in Kenya. No regular seasonal fluctuations were found in the number of hares recorded due probably to the continuous breeding of these equatorial species. The number of waterbuck seen in Uganda on moonlit nights was significantly greater than that counted on dark nights. This is not thought to be due to better viewing conditions under a full moon since the phenomenon was not found with other species. The number of hares recorded varied inversely with the number of other mammals present but bore no relationship with the number of birds. It is concluded that night counts can be useful in revealing population trends but not for assessing total numbers or for comparing densities in different areas.     

GENETIC STRUCTURE OF THE WESTERN NORTH AMERICAN AQUATIC GASTROPOD GENUS TAYLORCONCHA AND DESCRIPTION OF A SECOND SPECIES

The Bliss Rapids Snail (Taylorconcha serpenticola) is a threatenedspecies that ranges along a short reach of the middle SnakeRiver in southern Idaho. Additional Taylorconcha populationsof uncertain taxonomic status have recently been discoveredin other portions of the Snake River basin (Owyhee River, lowerSnake River). We investigated the phylogenetic relationshipsand population structure of these snails, together with twooutgroups, using cytochrome c oxidase subunit I (COI) of mitochondrialDNA and the first internal transcribed spacer region betweenthe 18S and 5.8S ribosomal DNA. These data show no sharing ofhaplotypes or genotypes among T. serpenticola and the Owyhee-LowerSnake populations, with both depicted as monophyletic unitswithin the Taylorconcha clade. Both of these datasets and morphologicalevidence suggest that the Owyhee-Lower Snake populations area distinct species, which we describe herein (T. insperata newspecies). Application of an available COI molecular clock suggeststhat Taylorconcha arose in the late Miocene, when ancestralSnake River drainage was impounded in an extensive lacustrinesystem (‘Lake Idaho’) in western Idaho. The shallowpopulation structuring of T. insperata suggests that the lowerSnake River was only recently colonized subsequent to incisionof Hells Canyon, draining of Lake Idaho, and development ofa through-going river in the late Neogene. The absence of significantgenetic structure in T. serpenticola, which is attributed tothe unstable course and flow regime of the middle Snake Riverduring the Quaternary, suggests that this species can be treatedas a single management unit. (Received 14 July 2005; accepted 23 September 2005)     

ALGAL COMMUNITY STRUCTURE OF THE EAST AND WEST FLOWER GARDEN BANKS,NORTHWESTERN GULF OF MEXICO

The algal communities of the Flower Garden Banks National Marine Sanctuary have not been comprehensively evaluated and only a few dominant macroalgal species have been reported. This study utilizes both destructive and non‐destructive sampling techniques to characterize and taxonomically identify the ‘algal mat’ community structure. The East and West Flower Garden Banks are located on the outer continental shelf approximately 200 km off the Texas‐Louisiana coastline. The average depth of both banks is 100 m with the crest approximately 20 m from the surface. Harvest and photogrammetric samples were collected during two extended cruises to the Flower Garden Banks in October 1998 and March 1999. Forty, 0.25‐m² quadrats of standing stock material were randomly collected along with one hundred sixty‐one 0.25 m² photo‐quadrats from an average depth of 27 m. Photo‐transparencies were projected to an actual size grid with 25 random points. Four thousand twenty‐five transparency points were evaluated and used to calculate percent composition of algal cover. Harvest samples were used to characterize the “algal mat” composition, species richness, abundance, and biomass. Forty‐two species were identified from the samples representing 14 Orders. The “red algal mat” was the dominant algal coverage comprising 38.4% of all photogrammetric samples. This mat was primarily composed of members from the Order Ceramiales. Centroceras, Ceramium, and Polysiphonia comprised 33.4% of the mat, Anotrichium and Hypoglossum, 22.4%.     

四川资中侏罗纪一新的半椎鱼类及其生物地层意义

本文记述的棘背天府鱼(新属新种)发现于四川资中沙溪庙组.它只有大的顶骨、少的次眶骨及无饰缘棘鳞等特征,与新鳞齿鱼(Neolepidotes)相似;另外具有很发达的棘状背嵴鳞、少的次眶骨及鳞片无杵臼式关节等特征,与半椎鱼(Semionotus)很相似.天府鱼以其长大的顶骨、较居后的颌关节、较短的眶前距、很发达的棘状背嵴鳞及无饰缘棘鳞等特征,有别于半椎鱼科中所有已知属.根据天府鱼和过去记述的鱼化石,仍认为含鱼层的时代可能为中佚罗世.     

PRESENCE AND DISTRIBUTION OF BROMINE IN THYSANOCLADIA DENSA (SOLIERIACEAE,GIGARTINALES), A MARINE RED ALGA FROM THE GREAT BARRIER REEF1

Electron-probe X-ray microanalysis of freeze dried sections of growing branch tips of Thysanocladia densa Sander shows high concentrations of bromine in the region of the medulla. Indirect evidence infers that the Br is associated with intercellular, granular deposits which accumulate within the mucilage of the medulla. The concentration of Br decreases in older regions of the thalli.