Nerita funiculata

Nerita funiculata, the funiculate nerite, is a species of marine gastropod in the family Neritidae found on the eastern Atlantic coast.

Nerita funiculata Temporal range: Pliocene–Recent PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Subclass:	Neritimorpha
Order:	Cycloneritida
Family:	Neritidae
Genus:	Nerita
Species:	N. funiculata
Binomial name
Nerita funiculata Menke, 1850
Synonyms
Nerita bernhardi Recluz, 1850[a] Nerita fulgurans var. bernhardi (Recluz, 1850) Nerita cerostoma Troschel, 1852 Nerita excavata G. B. Sowerby II, 1883 Nerita genuana Reeve, 1855 Nerita granulata Reeve, 1855 Nerita regalis Hupé, 1858

Classification

The species Nerita funiculata was named and scientifically described in 1850 by Karl Theodor Menke in a German article the title of which rougly translates to "Shells from Mazatlan, with critical notes".^[1] The article was published in the eleventh issue of the sixth volume of Zeitschrift für Malakozoologie, a monthly journal then edited by Menke and Ludwig Pfeiffer.^[2] N. funiculata is placed in the family Neritidae, a diverse group of snail species found in marine, brackish, and freshwater environments in the tropics and subtropics.^[3]

Synonyms

In the 1800s, numerous other Nerita species were described, only to be found to be synonymous with N. funiculata later on. In taxonomy, a synonym is a species determined to be the same as another, or as the ICZN terms it more formally, "each of two or more names of the same rank used to denote the same taxonomic taxon." The oldest name used to descibe a species is said to be given priority; a name given later is termed a junior synonym. Objective synonyms are species which are synonymous because they were described from the same type material; while subjective synonyms are just that – subjective – up for debate and "only a matter of individual opinion" as to whether the two species are the same and thus synonymous.^[4]

Reeve's species

In his "Monograph of the genus Nerita", published in 1855, Lovell Augustus Reeve described two new species of Nerita, N. genuana, and N. granulata,^[5] which would later all be synonymized with N. funiculata, which had been described five years prior.^[b][6] Reeve also validated the name N. bernhardi, which had been a nomen nudum.^[7] According to Leo George Hertlein and A.M. Strong in an article published in a 1955 Bulletin of the American Museum of Natural History, N. bernhardi had been "cited by Recluz in 1850 without a description or illustration. So far as we have ascertained, bernhardi was first described and illustrated by Reeve in 1855. It appears then that the first valid name for this species is Nerita funiculata Menke, dated November 11, 1850."^[8] N. funiculata being the first valid name for the species is important as that name thus gets taxonomic priority.^[4] The 1888 Manual of Conchology by George Tryon and Henry Pilsbry considered N. funiculata and genuana junior synonyms of "Nerita fulgurans var. bernhardi". The Manual described "var. bernhardi" as having colour varying from black to spotted with "yellowish grey or orange" and a shape somewhat flatter than N. fulgurans.^[9] This vague characterization roughly agrees with Reeve's more detailed description of N. bernhardi, which he wrote had a "rather depressed" shell with the "spire obtusely flattened" with colour "black, variegated with pale green, or yellowish dots".^[10] Hertlein and Strong's description of N. funiculata describes the species as having a roughly spherical shell, low spire, and having a colour that ranged from black to blotched with yellowish grey or orange.^[8] Indeed, Menke noted in his original description of N. funiculata that the species could appear with black variegation. He also wrote (in German): "At first glance, I considered this species, based on its size, inner lip, and colour, to be one of the countless forms of Ner. tessellata, especially since the tile-shaped leaflets that densely cover the ribs are lost through friction and age, and the outermost black layer of the shell also peels off in places, leaving the shell with white spots."^[1] Eduard von Martens, in his 1889 Die Gattungen Nerita und Neritopsis, distinguished between "Nerita Bernhardi", of which N. funiculata as described as Menke was a synonym, and N. funiculata as described by Reeve, which he considered a separate, valid species. Von Martens' N. Bernhardi was described as "blackish or obscurely buff, densely black-lined, with rare white spots", with a short spire, sub-spherical shape, and from eighteen to twenty four prominent ribs, while the species he accepted as N. funiculata was sub-spherical, more densely ribbed (30 to 35 narrow, darker ribs), had a prominent spire and was "dull, earth-colored gray-brown, with sparse, lighter, small spots.".^[11]

Henry Drummond Russell, in his 1940 PhD dissertation, proposed N. genuana be made a synonym of N. funiculata, as he noted that it "coincides" with Menke's species "in color, shape, and size",^[12] although the 1888 Manual already considered the two species synonymous, predating Russell by half a century.^[9] Reeve and von Martens both described N. genuana as a "jet-black species" with two prominent yellow or pink bands; like N. bernhardi, N. genuana had a "rather depressed" shell with a flattened spire.^[13][14] Nerita granulata, meanwhile, was still an accepted species in 1887, according to G. B. Sowerby II,^[15] and the 1888 Manual of Conchology accepted it and gives a one-sentence description.^[16] Today N. granulata is accepted as a synonym of N. funiculata.^[6]

The three other synonymous names

Three other species of Nerita were described in the 1800s which have since been found to be synonymous with N. funiculata. Nerita cerostoma was described by Franz Troschel in 1852. Troschel's new species, published in Archiv für Naturgeschichte, was black, had 22 ribs, and a short spire.^[17] The species was accepted by Tryon and Pilsbry (1888),^[18] von Martens (1889),^[19] and Dall (1910),^[20] but is now regarded as another junior subjective synonym.^[6] Nerita excavata, now considered a synonym, was described by Sowerby in 1883;^[6] the Manual of Conchology of 1888 accepted it but quietly noted that it was "apparently not very different from N. granulata, Reeve".^[16] Nerita regalis, described by Hupé in 1858, is also a synonym; it is not mentioned in Tryon and Pilsbry nor in von Martens.^[6]

• 
  Title page of Menke's journal article in 1850 which included the original description of Nerita funiculata.
• 
  Comparison of N. funiculata (as circumscribed and drawn by Reeve), and his illustrations of the three species he described which were later synonymized with N. funiculata.

N. funiculata is sometimes called the "funiculate nerite",^[21][22][23] while Reeve called it the "corded nerite".^[24]

Distribution

Nerita funiculata is distributed from Peru north to the upper tip of the Gulf of California and around Cocos Island.^[8] N. funiculata is also found in the Galápagos Islands: it has been observed in waters around Isla Santiago, Isla Santa Cruz, Isla Marchena, Isla de San Cristóbal, and Isla Genovesa, but not the archipelago's largest island, Isla Isabela.^[21]

Fossils

N. funiculata fossils have been found dating to the Pliocene epoch.^[8]

Notes

1. Also cited as Recluz, 1855 or Reeve, 1855
2. These three species weren't the only ones described by Reeve that year; others, such as Nerita balteata, remain accepted species.