Tag Archive for Taxonomy

New ant species described from Fiji – Proceratium vinaka

February 3, 2015 2 comments

Francisco Hita Garcia, known more familiarly as Paco, took the lead on describing a newly discovered species of Proceratium from Fiji [1]. Vinaka is the Fijian word for thank you. My friend Moala Tokota’a told me it is the most important word in the whole language.

Proceratium vinaka

Proceratium vinaka — a new species of ant described from Fiji

To call this blind, inconspicuous species rare is rather understated. In fact, there is only one single individual worker of this species ever collected in the whole wide world. I remember the moment I first laid eyes on it. A group of us including Rosie Gillespie, some of the crew from WCS and my wife Julia were working our way down from the misty peak of Mt. Devo (Vanua Levu) after a long day. There is a single track unsealed road we were following that winded down the mountain. The upper elevations of Mt. Devo are as pristine a forest as one will find in Fiji, but there was an old garden site on the way down that was transitioning back to jungle.

Distribution map of Fijian Proceratium species

Distribution map of Fijian Proceratium species

I was scanning the ground on hand and knee, searching for a last score before heading back to the truck, when this slow-moving stout and armored ant caught my eye. It looked out of place foraging on the surface. The line from Notorious B.I.G. shoot first ask questions last compelled me to get this special creature secured in a vial before it went to ground in the leaf litter. I stuck around for a few more minutes hoping to find more of its kin, but to no avail.

That was ten years ago. Since then this single specimen has been mounted on an insect pin together with various labels detailing the location, date and circumstances of its capture. It has been resting quietly in an insect cabinet, the sole known representative of its species, awaiting a name. Thanks to the effort of Paco and Evan, Proceratium vinaka is the 12th new ant species we’ve described from Fiji over the past decade. Only 34 more to go!

[1] Hita Garcia F, EM Sarnat, EP Economo (2015) Revision of the ant genus Proceratium Roger (Hymenoptera, Proceratiinae) in Fiji. ZooKeys 475: 97-112. doi:10.3897/zookeys.475.8761 [pdf]

Field Research, Fijian Ants , , ,

Pheidole flavens-complex introduced to the southwestern Pacific

November 21, 2014 No comments

Here’s the story behind the new Bioinvasions Records article on that just came out. Christian Rabeling and Ed Wilson went to Vanuatu a few years back in 2011 because it was one of the few Melanesian islands that Wilson had never collected from. They collected all the ants they could find in a general survey and kindly sent their Pheidole to the Economo lab at OIST so that I could match them against our other Pacific Pheidole collections and Evan could include them in our phylogenetic analysis. Christian and Ev caught some great Pheidole from the island, including this beautifully spinescent endemic from the sexspinosa complex shown below (CASENT0282641).

An elegant Vanuatu endemic ant species (Pheidole epem198, CASENT0282641) from the Pheidole sexspinosa complex

But one species came out in an unexpected branch on the phylogeny. Instead of coming out with the Old World clade with all the other native Melanesian ants, this one species was reliably nested within the New World clade. It’s closest relatives on the tree were two species that had been included in Corrie Moreau’s 2008 Pheidole phylogeny and id’d as P. moerens and P. flavens–both of which are considered to be invasive.

Major worker of a species from the Pheidole flavens-complex from Espiritu Santo, Vanuatu; collection code CR111110-15, specimen code CASENT0248836. (1) Lateral view, (2) fullface view, (3) dorsal view, (4) hypostomal bridge.

Major worker of a species from the Pheidole flavens-complex from Espiritu Santo, Vanuatu; collection code CR111110-15, specimen code CASENT0248836. (1) Lateral view, (2) fullface view, (3) dorsal view, (4) hypostomal bridge.

Plate-1-02

Minor worker of a species from the Pheidole flavens-complex from Espiritu Santo, Vanuatu; collection code CR111110-15, specimen code CASENT0248835. (5) Lateral view, (6) fullface view, (7) dorsal view

We wanted to let other researchers know about the spread of this trampy species into the Pacific, so we wrote up a rapid communication article for Bioinvasions Records. The idea was to get the basic information about the new discovery out as quickly as possible, so others in the region could be on the lookout for additional incursions.

The most frustrating part of this study was trying to get a name on the species. Unfortunately, the taxonomy of P. flavens and its close relatives like P. moerens and P. exigua is a super sticky mess, rife with infra-specific names, lost holotypes, and inaccurate determinations. It seems like these taxonomic morasses plague trampy species (like P. flavens and friends) much more often than your average ant species.

Why is it that trampy species so often belong to species-complexes? What are species-complexes, anyways? I suppose I’d define them as geographically distinct populations that are somewhere on the continuum of streching from a recently coalesced species radiation on one end to a network of geographically isolated groups with some low amount of gene flow still persisting. For the taxonomist or even the molecular systematist there is no clear way to know whether to call these things five geographically isolated species or one widespread species.

Whatever the population on Vanuatu turns out to be, it doesn’t match the neotype of P. flavens or the syntypes of P. moerens, so for now we have to settle for calling it a member of the flavens-complex and hope that someone tries to untangle this taxonomic knot in the near future.

EM Sarnat, C Rabeling, EP Economo & EO Wilson (2014) First record of a species from the New World Pheidole flavens-complex (Hymenoptera: Formicidae) introduced to the southwestern Pacific. Bioinvasions Records 3: 301-307. | PDF

 

Introduced Ants, Published research , , ,

How to identify Solenopsis invicta using Antkey

November 15, 2014 No comments

In this tutorial I demonstrate a few different approaches to identifying Solenopsis invicta, also known as the Red Imported Fire Ant (RIFA), using Antkey. The key can be accessed at antkey.org/content/key.

How to identify Solenopsis invicta using Antkey from Eli Sarnat on Vimeo.

How-to, Introduced Ants, Lucid Keys , , , , , ,

How to use Antkey’s Lucid3 interactive key

November 14, 2014 No comments

In this tutorial I demonstrate how to make the most effective use of Antkey’s interactive Lucid3 key for identifying invasive and introduced ants. There are tips on how to use features like the ‘best’ and ‘next best’ buttons, what the different panels mean, how to make effective use of thumbnail and pop-up images and how to adjust the text size.

How to use Lucid Key for identifying ants from Eli Sarnat on Vimeo.

How-to, Introduced Ants, Lucid Keys , , ,

New line drawings for undescribed Fijian Pristomyrmex

November 30, 2012 2 comments

Here are a few line drawings I am working on for the description of an undescribed species of Fijian Pristomyrmex. In the Ants of Fiji monograph, this species is listed as Pristomyrmex sp. FJ02.

Full face view of Pristomyrmex sp. FJ02. Line drawings can allow for better representation of important taxonomic features compared to specimen photographs. For example, the mandibular tooth structure is essential for Pristomyrmex species identification. The mandibular teeth on the specimen photograph used as a template for this illustration were obscured and difficult to see. The line drawing shows them quite clearly.

Rendering the characteristic foveae (circular depressions) of Pristomyrmex was a bit challenging, and I am sure my method could use some improvement. I began by using the Ellipse Tool to get the basic shapes, and then rotated them according to the template specimen. Next I used the eraser tool to break the foveae that appeared somewhat shallow. I then selected all the ‘broken’ foveae and applied a stroke profile that tapers strongly on both ends. For the ‘unbroken’ foveae I selected each individually and used the Width Tool to constrict the ellipses at a single point.

Profile of Pristomyrmex sp. FJ02. Of the over 50 known species of Pristomyrmex, this is only the second that lacks propodeal spines. The other, P. inermis, occurs in New Guinea.

I also used a new technique for the hairs on this illustration. I decided to use the Outline Stroke function for all of the hairs, and selected a white outline stroke. This allows for a white break where hairs overlap the ant profile and other strokes.

Fijian Ants, Illustrations , , ,

The Ants of Fiji – Print and PDF out now

November 20, 2012 2 comments
Figure 1. Photographs of Fijian ants. A) Acropyga sp. FJ02 (endemic) carrying mealybug. B) Hypoponera eutrepta (endemic) carrying larva. C) Tetramorium lanuginosum (introduced). D) Camponotus dentatus (endemic). E) Odontomachus simillimus (Pacific native). F) Camponotus polynesicus (endemic).

The print and full color, open-access pdf versions of the Ants of Fiji (Sarnat & Economo, 2012) are now available. The 400-page monograph reviews the entire known Fijian ant fauna, and includes the results of a recently completed archipelago-wide biodiversity inventory. A total of 187 ant species representing 43 genera are recognized here with an illustrated key to genera, synopses of each species, keys to species of all genera, and a species list. The work is heavily illustrated with specimen images, distribution maps, and habitat elevation charts.

Citation

Sarnat, E.M. & Economo, E.P. (2012) Ants of Fiji. University of California Publications in Entomology, 132, 1-398. [pdf]

 

Expert from the introduction section

Biologists have long sought to document and understand the unique evolution and ecology of island biotas. Oceanic archipelagos are often adorned with spectacular evolutionary radiations and unique ecosystems. These distinctive faunas, however, are highly vulnerable to human activities, climate change, and introduction of exotic species. Among island ant faunas, perhaps nowhere are these themes so prominently on display as in the Fijian archipelago.

The Fijian terrestrial biota was assembled during approximately 20 million years of over-water colonization, in situ evolution and speciation, and more recently through the arrival of species as stowaways on canoes, galleys and battleships (Figure 1). Today’s Fijian ant fauna is characterized by extreme geographic isolation from source areas, differentiation and pattern formation among islands, and contemporary invasions. The list of species occurring in Fiji, which continues to grow, includes both widespread dominant species and rare taxonomic oddities.

The motivation of this study is to provide an update to W. M. Mann’s (1921) monograph The Ants of the Fiji Islands, published 89 years ago. At the time, Mann lamented that the insect fauna of Fiji had been almost entirely neglected, and the limited knowledge accrued in the years since his publication is even more lamentable. With the recent collection of a large number of ant specimens in recent years, and a surge of interest in biodiversity research and conservation in Fiji, the opportunity has arrived to synthesize the taxonomy of the Fijian ant fauna for new generations of biologists. Our goal is to provide a resource that will allow a scientist to collect an ant specimen anywhere in Fiji and connect it to information on its taxonomy, geographic distribution, habitat distribution and natural history. With 187 species distributed over seven islands of moderate size, and hundreds of smaller islands, the system represents a diverse yet tractable fauna that can be useful for testing hypotheses in evolutionary biology, island biogeography, community ecology, invasion biology and other disciplines.

It would be remiss to conclude this introduction without a note of recognition and thanks to the people of Fiji. Mann (1921) wrote in the introduction of his own treatise on Fijian ants, “I shall remember the native Fijians…as the kindliest, most hospitable folk I have known.” Eighty-nine years later, we both share those sentiments and add our admiration for the Fijians’ thoughtful stewardship of their native lands. We hope this small study will be useful for scientific discovery and conservation of Fiji’s fascinating natural heritage in the generations to come.

Field Research, Published research , ,