scholarly journals The rise of ocean giants: maximum body size in Cenozoic marine mammals as an indicator for productivity in the Pacific and Atlantic Oceans

2016 ◽  
Vol 12 (7) ◽  
pp. 20160186 ◽  
Author(s):  
Nicholas D. Pyenson ◽  
Geerat J. Vermeij
Keyword(s):  
Body Size ◽  
Marine Mammals ◽  
Marine Invertebrate ◽  
North Pacific Ocean ◽  
Feeding Guilds ◽  
Feeding Guild ◽  
Evolutionary Patterns ◽  
The North ◽  
Maximum Body ◽  
Maximum Body Size

Large consumers have ecological influence disproportionate to their abundance, although this influence in food webs depends directly on productivity. Evolutionary patterns at geologic timescales inform expectations about the relationship between consumers and productivity, but it is very difficult to track productivity through time with direct, quantitative measures. Based on previous work that used the maximum body size of Cenozoic marine invertebrate assemblages as a proxy for benthic productivity, we investigated how the maximum body size of Cenozoic marine mammals, in two feeding guilds, evolved over comparable temporal and geographical scales. First, maximal size in marine herbivores remains mostly stable and occupied by two different groups (desmostylians and sirenians) over separate timeframes in the North Pacific Ocean, while sirenians exclusively dominated this ecological mode in the North Atlantic. Second, mysticete whales, which are the largest Cenozoic consumers in the filter-feeding guild, remained in the same size range until a Mio-Pliocene onset of cetacean gigantism. Both vertebrate guilds achieved very large size only recently, suggesting that different trophic mechanisms promoting gigantism in the oceans have operated in the Cenozoic than in previous eras.

scholarly journals Redescription of Ochmacanthus batrachostoma (Miranda-Ribeiro, 1912) (Siluriformes: Trichomycteridae): a possible case of incipient paedomorphism

2016 ◽  
Vol 14 (1) ◽  
Author(s):  
Caio S. Neto ◽  
Mário de Pinna
Keyword(s):  
Body Size ◽  
Internal Anatomy ◽  
Morphometric Traits ◽  
Type Specimens ◽  
Caudal Peduncle ◽  
Caudal Fin ◽  
Maximum Body ◽  
Maximum Body Size

ABSTRACT The lepidophagous stegophiline catfish Ochmacanthus batrachostoma (Miranda-Ribeiro, 1912) is endemic to the Paraná-Paraguai basin and is the only member of its genus in that drainage. It remains a poorly-known taxon mainly due to the historical scarcity of study specimens. The species is herein redescribed on the basis of type and non-type specimens from Brazil, Argentina and Paraguay. Ochmacanthus batrachostoma can be distinguished from congeners by the presence of long maxillary and rictal barbels, reduction of the posterior end of the caudal peduncle, a tadpole-like caudal fin and peduncle, among other morphometric traits and features of internal anatomy. Comparisons show that a number of unique traits of adult O. batrachostoma resemble conditions seen in juvenile specimens of other members of Stegophilinae. Such traits are also more pronounced in juveniles of O. batrachostoma itself. The species also has the smallest maximum body size in Ochmacanthus and among the smallest of any stegophiline. In combination, such observations suggest that the species is paedomorphic, although to a degree less extreme than seen in some other trichomycterids. This is the first possible case of paedomorphosis identified for stegophilines.

MAXIMUM BODY SIZE IN A RADIATING CLADE AS A FUNCTION OF TIME

Evolution ◽  
2005 ◽  
Vol 59 (5) ◽  
pp. 941
Author(s):  
Jerzy Trammer
Keyword(s):  
Body Size ◽  
Maximum Body ◽  
Maximum Body Size

Perisesarma tuerkayi, a new species of mangrove crab from Vietnam (Decapoda, Brachyura, Sesarmidae), with an assessment of its phylogenetic relationships

Crustaceana ◽  
2017 ◽  
Vol 90 (7-10) ◽  
pp. 1155-1175 ◽  
Author(s):  
Adnan Shahdadi ◽  
Peter J. F. Davie ◽  
Christoph D. Schubart
Keyword(s):  
New Species ◽  
Body Size ◽  
Nuclear Dna ◽  
Congeneric Species ◽  
Southern Vietnam ◽  
Mangrove Crab ◽  
Large Maximum ◽  
Maximum Body ◽  
Maximum Body Size ◽  
A New Species

A new species ofPerisesarma,P. tuerkayi, is described from mangroves of Tan Thoi Island, southern Vietnam. Morphologically, the new species differs most significantly from congeners by the tuberculation pattern of the chelar dactylus, its unique G1 morphology, an unusually large maximum body size, and relatively short and broad ambulatory legs. Genetically,P. tuerkayin. sp. is markedly divergent from other congeneric species, both in mitochondrial and nuclear DNA. It is the fifth species ofPerisesarmareported from Vietnam.

Trophic relationships of albatrosses associated with squid and large-mesh drift-net fisheries in the North Pacific Ocean

1997 ◽  
Vol 75 (4) ◽  
pp. 549-562 ◽  
Author(s):  
Patrick Gould ◽  
Peggy Ostrom ◽  
William Walker
Keyword(s):  
Pacific Ocean ◽  
Trophic Level ◽  
North Pacific ◽  
Marine Mammals ◽  
North Pacific Ocean ◽  
Transitional Zone ◽  
Trophic Relationships ◽  
Commercial Fishing ◽  
The North ◽  
The North Pacific

The diets of Laysan (Diomedea immutabilis) and black-footed albatrosses (D. nigripes) killed in squid and large-mesh drift nets in the transitional zone of the North Pacific Ocean were investigated by examining the contents of the digestive tracts and determining δ13C and δ15N values in breast-muscle tissue. The results show that (i) the combined prey of the two species of albatross consists of over 46 species of marine organisms including coelenterates, arthropods, mollusks, fish, and marine mammals; (ii) both species supplement their traditional diets with food made available by commercial fishing operations (e.g., net-caught squid and offal); (iii) while obtained from drift nets, diets of nonbreeding Laysan and black-footed albatrosses are dominated by neon flying squid (Ommastrephes bartrami); (iv) in the absence of drift-net-related food, Laysan albatrosses feed most heavily on fish and black-footed albatrosses feed most heavily on squid; and (v) based on δ15N values, nonbreeding adult Laysan albatrosses from the transitional zone of the North Pacific Ocean and Laysan albatross nestlings fed by adults from Midway Island in the subtropical Pacific feed at one trophic level and one-third of a trophic level lower than black-footed albatrosses, respectively.

Fecundity and Reproductive Output in Nine Species of Cancer crabs (Crustacea, Brachyura, Cancridae)

1991 ◽  
Vol 48 (2) ◽  
pp. 267-275 ◽  
Author(s):  
Anson H. Hines
Keyword(s):  
Body Size ◽  
Reproductive Output ◽  
Reproductive Traits ◽  
The North ◽  
Female Body Size ◽  
Body Weights ◽  
Order Of Magnitude ◽  
Maximum Body ◽  
The North Pacific ◽  
Female Weight

The major variables of reproductive output and fecundity were compared among brooding females of nine species of Cancer from the North Pacific and North Atlantic: C. oregonensis, C. gracilis, C. irroratus, C. antennarius, C. productus, C. borealis, C. anthonyi, C. magister, and C. pagurus. Female body size is the principal determinant of reproductive output, with dry body weights spanning two orders of magnitude from 1.2 to 199.5 g among species and often one order of magnitude within species. Mean dry brood weights ranged from 0.21 to 26.7 g among species, with relative brood size varying from 11 to 19% of female weight. The brood mass is partitioned into eggs ranging among species from 311 to 442 μm, resulting in mean fecundities ranging among species from 18 200 to 2 208 000 eggs per brood. Most species produce one or two broods per year over the winter–spring season over a reproductive span averaging 6.6 yr (range 4–10 yr). Cumulative reproductive output and cumulative fecundity over the maximum estimated life span exhibited approximately isometric functions of maximum body size, and they ranged among species from 1.88 to 316 g brood weight and 158 000 to 22 300 000 eggs per lifetime, respectively. The pattern of covariation of reproductive traits in the Cancridae corresponds well with the overall pattern previously determined for a diverse array of brachyurans from seven families.

Secular Changes in the Body Size of Non-Military Populations

1978 ◽  
Vol 22 (1) ◽  
pp. 616-616
Author(s):  
Howard W. Stoudt
Keyword(s):  
Health Care ◽  
Body Size ◽  
Western Europe ◽  
Economic Status ◽  
The Body ◽  
Past Century ◽  
The Past ◽  
Military Populations ◽  
Maximum Body ◽  
Maximum Body Size

People are getting bigger. Overall increases in body size can be documented for various worldwide populations for which adequate anthropometric data are available. In Western Europe and North America the increase in adult stature over the past century has commonly approximated one centimeter per decade, though with some variability between different groups. Other body dimensions, as well as weight, have also been increasing in both men and women and in different ethnic groups. The most likely explanations for such increases in body size are improved nutrition and better health care during growth years. Since such factors tend to be associated with higher socio-economic status, it is these groups who have demonstrated the most marked increases in body size in recent years. Many upper socio-economic groups have already attained most or all of their maximum body size potential, and will experience little further increase. On the other hand, those presently less favored groups who can still benefit from improved nutrition and health care will continue to show increases in body size until they also have reached their maximum potential.

Sign in / Sign up

Export Citation Format

Share Document