Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New Fish Species Offers Literal Take on ‘Hooking Up’

28.09.2012
Fishing hooks aren’t the only hooks found in east-central Mexican waters.

A new species of freshwater fish described by a North Carolina State University researcher has several interesting – and perhaps cringe-inducing – characteristics, including a series of four hooks on the male genitalia.


A magnified view of the four hooked genitalia of the newly identified fish species Gambusia quadruncus.

Females of the new species – the llanos mosquitofish, or Gambusia quadruncus – also have distinguishing characteristics, including a colorful anal spot.

A paper describing the new species, which lives in a diversity hotspot and seemingly branched off from its closest relative more than one million years ago, appears in the Journal of Fish Biology.

Dr. Brian Langerhans, assistant professor of biology at NC State and the lead author of the paper, says that these interesting characteristics may play important roles in mating control and success.

While more research is needed, Langerhans says that four-hooked genitalia on males can serve a purpose when females attempt to block or restrict mating attempts.

“Typically, reproduction is more costly in females, so females favor ways of reducing mating with ‘lower quality’ males,” Langerhans says, “but reproduction is cheap in males and so selection favors ways of mating with as many females as possible. In Gambusia, some females, including G. quadruncus, have evolved modifications that appear to function as a blocking device – essentially a big ball of tissue blocking most of the genital pore – restricting entry of the male’s gonopodial tip. Thus, the female would have to behaviorally allow the male to mate or the male would have to evolve a counter response to avoid this problem.”

The four-hooked genitalia could be that counter-response, Langerhans says.

“Having four hooks on the gonopodium may provide a means of overcoming female resistance, latching on to the gonopore and transferring sperm in a manner that facilitates effective sperm transfer. Or it may serve to stimulate the female in a manner that causes responses in the female that facilitate effective sperm transfer,” Langerhans says.

Somewhat similarly, the colorful anal spot on females appears to serve as a signal that only certain males are desired for mating.

“The differing, species-specific female anal spots appear to influence male mating behavior by signaling the location of the gonopore to the male, sometimes indicating the reproductive status of the female, and distinguishing fish of their own species from fish of other species to reduce costly cross-breeding, which can result in fish with reduced fitness,” Langerhans says. “So it may be that G. quadruncus evolved different anal spots to help reduce interspecies matings and possible formation of hybrids.”

- kulikowski -

Note to editors: An abstract of the paper follows.

Gambusia quadruncus (Cyprinodontiformes: Poeciliidae): A new species of mosquitofish from east-central Mexico

Authors: Brian Langerhans, North Carolina State University; et al

Published: September 2012, in Journal of Fish Biology

Abstract: Gambusia quadruncus n. sp., the llanos mosquitofish, is described from east-central Mexico. The region inhabited by the species represents a hotspot of diversity of Gambusia, and G. quadruncus sometimes coexists with at least three congeners. The species differs from its closest relative, Gambusia affinis, in several characteristics with plausible effects on reproductive isolation, e.g. body size, body and fin morphology, male genital morphology (distal tip of gonopodium) and female anal spot morphology (colouration near the urogenital sinus). Moreover, combined analysis of mitochondrial and nuclear gene sequence data (c. 2158 total base pairs) indicates reciprocal monophyly of G. quadruncus and its sister species G. affinis, with levels of genetic divergence suggesting the two species diverged from one another over a million years ago. The origin of G. quadruncus may reflect a vicariant event associated with Pliocene orogenesis in the Tamaulipas Arch and a frontal section of the Sierra Madre Oriental (Lleran Mesas). Gambusia quadruncus inhabits a variety of freshwater habitats across several river drainages, with its range spanning at least 350 km from north to south, covering over 25 000 km2. A key to aid identification of the species is provided.

Dr. Brian Langerhans | EurekAlert!
Further information:
http://www.ncsu.edu

More articles from Ecology, The Environment and Conservation:

nachricht Preservation of floodplains is flood protection
27.09.2017 | Technische Universität München

nachricht Conservationists are sounding the alarm: parrots much more threatened than assumed
15.09.2017 | Justus-Liebig-Universität Gießen

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

Im Focus: New nanomaterial can extract hydrogen fuel from seawater

Hybrid material converts more sunlight and can weather seawater's harsh conditions

It's possible to produce hydrogen to power fuel cells by extracting the gas from seawater, but the electricity required to do it makes the process costly. UCF...

Im Focus: Small collisions make big impact on Mercury's thin atmosphere

Mercury, our smallest planetary neighbor, has very little to call an atmosphere, but it does have a strange weather pattern: morning micro-meteor showers.

Recent modeling along with previously published results from NASA's MESSENGER spacecraft -- short for Mercury Surface, Space Environment, Geochemistry and...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

Conference Week RRR2017 on Renewable Resources from Wet and Rewetted Peatlands

28.09.2017 | Event News

 
Latest News

A single photon reveals quantum entanglement of 16 million atoms

16.10.2017 | Physics and Astronomy

The melting ice makes the sea around Greenland less saline

16.10.2017 | Earth Sciences

On the generation of solar spicules and Alfvenic waves

16.10.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>