How many species are there?

On the number of species on Earth and in the ocean

A larger selection of photos can be found HERE Below are some of the thousands of new species described each year, per FIGURE 2 in the PLoS Biology paper. Media using these photos must credit the photographer as indicated. Click on a photo to download it in high resolution.
Actinopterygii Photo Credit: David Hall Please contact the author (david@seaphotos.com) for uses other than the cover of the Journal PLoS Biology Species Name: Histiophyrne psychedelica Described by: Pietsch, Arnold & Hall, 2009 An earlier specimen was collected in 1992 and misidentified as Histiophryne cryptacanthus. The specimen was preserved and placed on a shelf. No one returned to it until a recent rediscovery in 2008 when DNA analysis clarified the species as new and its description made the headlines of news outlets worldwide .	Amphibia Photo Credit: Alejandro Arteaga Species Name: Pristimantis gagliardoi Described by: Lehr, Moravec & Gagliard, 2010 The species was collected in the high Andes of southeastern Ecuador.	Annelida Photo Credit: Yoshihiro Fujiwara/JAMSTEC Species Name: Vigtorniella sp. A possible new species of polychaete worm. It was collected at the whale fall sampling habitat in Sagami Bay at a depth of 925 meters.
Arachnida Photo Credit: Jeremy Miller Species Name: Eriauchenius ambre Described by: Wood 2008 This species from the family Archaeidae was discovered along with nine other new species of spiders in Madagascar. The species are characterized by their unusually long necks and jaws and that they eat other spiders.	Aves Photo Credit: Dario Sanches Species Name: Thalurania nigricapilla Described by: Valdés & Schuchmann, 2009	Chilopoda Photo Credit: Eric Guinther Species Name: Scolopendra sp
Ctenophora Photo Credit: Marsh Youngbluth Species Name: Bathocyroe fosteri Described by: Madin & Harbison, 1978	Diplopoda Photo Credit: Franco Folini Species Name: Harpaphe haydeniana Described by: Wood, 1864	Echinodermata Photo Credit: Heloise Chenelot Species Name: Aleutihenricia federi Described by: Clark & Jewett, 2010 This new species of sea star was photographed off Green Island, Bay of Isles, Adak Island at a depth of 16 meters.
Hemichordata Photo Credit: Derek Siveter Species Name: Galeaplumosus abilus Described by: Hou, Aldridge, Siveter, Williams, Zalasiewicz & Ma, 2011 This new species hemichordate is a fossil that lived on Earth some 525 million years ago.	Insecta Photo Credit: Shipher Wu Species Name: Herochroma supraviridaria Described by: Inoue, 1999	Mammalia Photo Credit: Paulo Canorus Species Name: Neofelis diardi Described by: World Wildlife Fund, 2007 Genetic research results clearly indicate that the clouded leopard of Borneo should be considered a separate species.
Mesozoa Photo Credit: Brockhaus & Efron Species Name: Mesozoa sp.	Mollusca Photo Credit: Yoshihiro Fujiwara, JAMSTEC Species Name: Alviniconcha sp. This snail inhabits deep-sea hydrothermal vents and harbors chemoautotrophic symbionts in its gills. This individual, found at the Sulyo Seamount, Tokyo hydrothermal vent, is probably a new species. Only a single specimen has been discovered to date.	Nemata Photo Credit: Gaetan Borgonie Species Name: Halicephalobus mephisto Described by: Borgonie, García-Moyano, Litthauer, Bert, Bester, van Heerden, Möller, Erasmus & Onstott, 2011 This species was found in the deep subsurface biosphere, over three kilometers into the Earth’s crust. Its discovery challenged the paradigm that this harsh environment was unique to single-cell organisms and had important implications for the search for subsurface life on other planets in our Solar System.
Pycnogonida Photo Credit: Steve Childs Species Name: Pycnogonid sp.	Reptilia Photo Credit: Alejandro Arteaga Species Name: Microlophus indefatigabilis Described by: Benavides, Baum, Snell & Snell, 2009 This species found on the Galapagos Islands was designated as a new species based on DNA analysis. It could have arrived on the island some two million years ago.	Rotifera Photo Credit: Gaetan Borgonie Species Name: Polyarthra