Belongs within: Crangonyctoidea.
On Niphargus
Published 12 October 2018
I’ve commented before on the unexpectedly high diversity of animal species that can be found living in groundwater. Because dispersal through this habitat is, unsurprisingly, often difficult and bodies of groundwater are often isolated from each other, many groundwater-adapted species can have almost ludicrously small ranges. Hence, for instance, the diversity of the amphipod genus Niphargus.
The genus Niphargus is found across Europe, mostly south of what was the lower edge of the northern ice sheet during the Pleistocene, though it is replaced by a closely related genus in the Iberian Peninsula. A few species are also found in south-west Asia. They are usually eyeless and colourless (the genus name means ‘snowy white’). Though clearly adapted for subterranean environments, they may also be found in associated surface habitats such as springs or the upper sections of streams (Fišer et al. 2015). Species of Niphargus vary considerably in size: the smallest interstitial species may be only two or three millimetres in length whereas some cave-dwellers reach forty millimetres (Karaman & Ruffo 1986). They may feed on organic particles filtered from the water, or they may predate on smaller animals.
Over 300 species of Niphargus are currently recognised, making it one of the largest genera of freshwater amphipods. Even so, this number is likely to be a significant underestimate of the genus’ true diversity. A number of studies on Niphargus have identified evidence of previously cryptic species. A study by Fišer et al. (2015) of two species from the Istrian Peninsula in the north-west Balkans found genetic evidence for the existence of two strongly divergent populations within each, with the two populations of ‘N. krameri‘ being morphologically as well as genetically distinct. Flot et al. (2010) found evidence of four distinct lineages within ‘N. ictus‘ of Italy’s Frasassi caves, representing at least three independent colonisations of the cave system from external sources. At least two of these lineages are unique among amphipods in living in a symbiotic association with sulphide-oxidising bacteria of the genus Thiothrix, allowing them to survive in Frasassi’s sulphide-rich waters.
With such a large genus, attempts have naturally been made to divide it into more manageable units. About a dozen species groups have been recognised on the basis of morphology, albeit some poorly defined. However, a molecular phylogenetic study of the genus by Fišer et al. (2008) identified none of these groups as monophyletic. Instead, they found a higher correlation of phylogeny with geography than morphology. The picture suggested is one of poor dispersers, re-evolving similar forms on multiple occasions as they diverge to exploit their secluded habitats as best they can.
Systematics of Niphargus
<==Niphargus Schiödte 1849KR86 [=Stygoniphargus Karaman 1952KR86; incl. StephanellniphargusB77] |--*N. (Niphargus) stygius (Schiödte 1847)KR86 [=Gammarus stygiusB77, N. (*Stygoniphargus) stygiusKR86] | |--N. s. stygiusKR86 | |--N. s. bosniacus Karaman 1943KR86 | |--N. s. brachytelson Karaman 1952KR86 | |--N. s. ‘danconai’ Karaman 1954 non N. danconai Benedetti 1942KR86 | |--N. s. karamani Schellenberg 1935KR86 | |--N. s. kenki Karaman 1952KR86 | |--N. s. likanus Karaman 1952KR86 | |--N. s. novomestanus Karaman 1952KR86 | |--N. s. podpecanus Karaman 1952KR86 | |--N. s. poloninicus Straśkraba 1957KR86 | |--N. s. ravanicanus Karaman 143KR86 | `--N. s. remyi Karaman 1934KR86 |--N. (Carpatoniphargus Karaman & Karaman 1959)KR86 | `--N. (*C.) carpathicus Dobreanu & Manolache 1939KR86 | |--N. c. carpathicusKR86 | |--N. c. affinis Dobreanu, Manolache & Puscariu 1953KR86 | |--N. c. cavernicolus Dobreanu & Manolache 1957KR86 | `--N. c. meridionalis Dobreanu & Manolache 1957KR86 |--N. (Jovaniphargus Karaman 1960)KR86 | `--N. (*J.) jovanovici Karaman 1931KR86 |--N. (Karamaniella Sket 1962)KR86 | `--N. (*K.) pupetta Sket 1962KR86 |--N. (Martynovia Derzhavin 1945)KR86 | `--N. (*M.) submersaKR86 |--N. (Orniphargus Karaman 1950)KR86 | `--N. (*O.) orcinus Joseph 1869KR86 | |--N. o. orcinusKR86 | `--N. o. redenseky Sket 1959KR86 |--N. (Phaenogammarus Dudich 1941)KR86 | `--N. (*P.) thermalis Dudich 1941KR86 |--N. (Protoniphargopsis Sket 1957)KR86 | `--N. (*P.) kochianus Bate 1859KR86 | |--N. k. kochianusKR86 | |--N. k. dimorphopus Stock & Gledhill 1977KR86 | |--N. k. irlandicus Schellenberg 1932KR86 | |--N. k. petrosani Dobreanu & Manolache 1933KR86 | `--N. k. polonicus Schellenberg 1936KR86 |--N. (Stygodytes Absolon 1916)KR86 | `--N. (*S.) balcanicus (Absolon 1927)KR86 `--N. (Supraniphargus Karaman 1950)KR86 `--N. (*S.) illidzensis Schäferna 1922KR86 |--N. i. illidzensisKR86 |--N. i. dalmatinus Schäferna 1922KR86 |--N. i. montenigrinus Karaman 1962KR86 |--N. i. orientalis Karaman 1950KR86 |--N. i. pannonicus Karaman 1950KR86 `--N. i. slovenicus Karaman 1932KR86 Niphargus incertae sedis: N. abchasicus Martynov 1932KR86 N. aberrans Sket 1972KR86 N. ablaskiri Birstein 1940KR86 |--N. a. ablaskiriKR86 |--N. a. georgievi Karaman & Karaman 1959KR86 |--N. a. inermis Birstein 1940KR86 |--N. a. romanicus Dobreanu & Manolache 1942KR86 `--N. a. variabilis Dobreanu, Manolache & Puscariu 1953KR86 N. abricossovi Birstein 1932KR86 |--N. a. abricossoviKR86 `--N. a. inornatus Derzhavin 1945KR86 N. adbiptus Karaman 1973KR86 N. adei Karaman 1934KR86 N. alasonius Derzhavin 1945KR86 N. altagahizi Alouf 1973KR86 N. alutensis Dancau 1971KR86 N. ambulator Karaman 1975KR86 N. anatolicus Karaman 1950KR86 N. andropus Schellenberg 1940KR86 N. angelieri Ruffo 1954KR86 N. aquilex Schiödte 1855 [incl. N. aquilex vejdovskyi Wrzesniowski 1890]KR86 N. arbiter Karaman 1985KR86 N. asper Karaman 1972KR86 N. auerbachi Schellenberg 1934KR86 N. bajuvaricus Schellenberg 1932KR86 |--N. b. bajuvaricusKR86 `--N. b. grandii Ruffo 1937KR86 N. balazuci Schellenberg 1951KR86 N. bihorensis Schellenberg 1940KR86 N. birsteini Dedyu 1963KR86 N. bitoljensis Karaman 1943KR86 N. borutzkyi Birstein 1933KR86 N. boskovici Karaman 1952KR86 |--N. b. boskoviciKR86 |--N. b. alatus Karaman 1973KR86 `--N. b. borkanus Karaman 1960KR86 N. boulangei Wichers 1964KR86 N. brevicuspis Schellenberg 1937KR86 |--N. b. brevicuspisKR86 `--N. b. sketi Karaman 1966KR86 N. brevirostris Sket 1971KR86 N. brixianus Rufo 1937KR86 N. bureschi Fage 1926KR86 N. burgundus Graf & Straškraba 1968KR86 N. buturovici Karaman 1958KR86 N. caelestis Karaman 1982KR86 N. canui Karaman 1976KR86 N. carsicus Straskarba 1956KR86 N. casimiriensis Skalski 1980KR86 N. castellanus Karaman 1960KR86 N. cepelarensis Karaman & Karaman 1959KR86 N. ciliatus Chevreux 1906KR86 |--N. c. ciliatusKR86 `--N. c. cismontanus Margalef 1952KR86 N. corinae Dedyu 1963KR86 N. costozzae Schellenberg 1935KR86 N. croaticus (Jurinac 1887)KR86 |--N. c. croaticusKR86 `--N. c. pachytelson Sket 1960KR86 N. cubanicus Birstein 1954KR86 N. cvijici Karaman 1950KR86 N. dacicus Dancau 1963KR86 N. danconai Benedetti 1942KR86 N. deelemanae Karaman 1973KR86 N. delamarei Ruffo 1954KR86 N. dimorphus Birstein 1961KR86 N. dobrogicus Dancau 1964KR86 N. dudichi Hanko 1924KR86 N. duplus Karaman 1976KR86 N. effosus Dudich 1943KR86 N. elegans Garbini 1894KR86 |--N. e. elegansKR86 `--N. e. zagrebensis Karaman 1950KR86 N. enslini Karaman 1932KR86 N. eugeniae Derzhavin 1945KR86 N. fontanus Bate 1859KR86 N. foreli Humbert 1877KR86 N. galenae Derzhavin 1939KR86 N. gallicus Schellenberg 1935KR86 N. galvagnii Ruffo 1953KR86 N. gebhardti Schellenberg 1934KR86 N. gineti Bou 1965KR86 N. glontii Behning 1940KR86 N. graecus Karaman 1934KR86 N. gurjanovae Birstein 1941KR86 N. hadzii Rejic 1956KR86 N. hebereri Schellenberg 1933KR86 N. hercegovinensis Karaman 1950KR86 N. hoverlicus Dedyu 1963KR86 N. hrabei Karaman 1932KR86 N. hungaricus Mehely 1937KR86 N. hvarensis Karaman 1952KR86 N. incertus Dobreanu, Manolache & Puscariu 1951KR86 N. inclinatus Karaman 1973KR86 N. inopinatus Schellenberg 1932KR86 N. jaroschenkoi Dedyu 1963KR86 N. jugoslavicus Karaman 1982KR86 N. kieferi Schellenberg 1936KR86 N. korosensis Dudich 1943KR86 N. krameri Schellenberg 1935KR86 |--N. k. krameriKR86 `--N. k. timavi Karaman 1954KR86 N. kurdus Derzhavin 1945KR86 N. labacensis Sket 1956KR86 N. ladmiraulti Chevreux 1901KR86 N. laisi Schellenberg 1936KR86 N. laticaudatus Schellenberg 1940KR86 N. latimanus Birstein 1952KR86 N. lattingerae Karaman 1983KR86 N. leopoliensis Jaworowski 1893KR86 N. lindbergi Karaman 1956KR86 N. longicaudatus Costa 1851KR86 |--N. l. longicaudatusKR86 |--N. l. corsicanus Schellenberg 1950KR86 |--N. l. thuringius Schellenberg 1934KR86 `--N. l. versluysi Karaman 1950KR86 N. longidactylus Ruffo 1937KR86 N. longiflagellum Karaman 1950KR86 N. lori Derzhavin 1945KR86 N. macedonicus Karaman 1929KR86 N. magnus Birstein 1940KR86 N. maximus Karaman 1929KR86 |--N. m. maximusKR86 |--N. m. petkovskii Karaman 1963KR86 `--N. m. vulgaris Karaman 1968KR86 N. melticensis Dancau & Andreev 1973KR86 N. microcerberus Sket 1972KR86 N. miljeticus Straškraba 1959KR86 N. minor Sket 1956KR86 N. moldavicus Dobreanu, Manolache & Puscariu 1953KR86 N. molnari Mehely 1927KR86 N. multipennatus Sket 1956KR86 N. nadarini Alouf 1972KR86 N. nicaensis Isnard 1916KR86 N. ohridanus Karaman 1929KR86 |--N. o. ohridanusKR86 `--N. o. fontophilus Karaman 1943KR86 N. pachypus Schellenberg 1933KR86 N. pancici Karaman 1929KR86 |--N. p. pancici (see below for synonymy)KR86 |--N. p. dojranensis Karaman 1960KR86 `--N. p. vlkanovi Karaman & Karaman 1959KR86 N. parapupetta Karaman 1984KR86 N. parenzani Ruffo & Vigna-Taglianti 1968KR86 N. parvus Karaman 1943KR86 N. pasquinii Vigna-Taglianti 1966KR86 |--N. p. pasquiniiKR86 `--N. p. sodalis Karaman 1984KR86 N. patrizii Ruffo & Vigna-Taglianti 1968KR86 N. pavicevici Karaman 1976KR86 N. pectinicauda Sket 1971KR86 N. pedemontanus Ruffo 1937KR86 N. pellagonicus Karaman 1943KR86 N. pescei Karaman 1984KR86 N. phreaticolus Motas, Dobreanu & Manolache 1948KR86 N. plateaui Chevreux 1901KR86 N. pliginskii Martynov 1930KR86 N. podgoricensis Karaman 1934KR86 N. ponoricus Dancau 1963KR86 N. potamophilus Birstein 1954KR86 N. pretneri Sket 1959KR86 N. pseudocaspius Karaman 1982KR86 N. pseudokochianus Dobreanu, Manolache & Puscariu 1953KR86 N. pseudolatimanus Birstein 1952KR86 N. pulevici Karaman 1967KR86 N. puteanus (Koch 1836)KR86 |--N. p. puteanusKR86 |--N. p. baloghi Dudich 1940KR86 |--N. p. banaticus Dobreanu & Manolache 1936KR86 |--N. p. carpathorossicus Straskraba 1957KR86 |--N. p. derzhavini Birstein 1952KR86 |--N. p. iniochus Birstein 1941KR86 |--N. p. komareki Karaman 1932KR86 `--N. p. otharicus Birstein 1952KR86 N. rajecensis Schellenberg 1938KR86 N. rejici Sket 1958KR86 N. rhenorhodanensis Schellenberg 1937KR86 N. rhodi Karaman 1950KR86 N. robustus Chevreux 1901KR86 N. romuleus Vigna-Taglianti 1968KR86 N. rostratus Sket 1971KR86 N. rucneri Karaman 1962KR86 N. ruffoi Karaman 1976KR86 N. salonitanus Karaman 1950KR86 N. sanctinaumi Karaman 1943KR86 N. schellenbergi Karaman 1932KR86 N. serbicus Karaman 1960KR86 N. setiferus Schellenberg 1937KR86 N. skopljensis Karaman 1929KR86 N. smederevanus Karaman 1950KR86 N. smirnovi Birstein 1952KR86 N. somesensis Motas, Dobreanu & Manolache 1948KR86 N. speziae Schellenberg 1936KR86 N. sphagnicolus Rejic 1956KR86 N. spoeckeri Schellenberg 1933KR86 |--N. s. spoeckeri [=N. puteanus spoeckeri]KR86 `--N. s. sibillinianus Karaman 1984KR86 N. stankoi Karaman 1974KR86 N. stefanellii Ruffo & Vigna-Taglianti 1968KR86 N. stenopus Sket 1960KR86 N. steueri Schellenberg 1935KR86 |--N. s. steueriKR86 |--N. s. kolombatovici Karaman 1950KR86 `--N. s. subtypicus Sket 1960KR86 N. strouhali Schellenberg 1933KR86 N. stygocharis Dudich 1943KR86 |--N. s. stygocharisKR86 `--N. s. italicus Karaman 1976KR86 N. submersus (Derzhavin 1945)KR86 N. tamaninii Ruffo 1953KR86 N. tatrensis Wrzesniowsky 1888 (see below for synonymy)KR86 N. tauri Schellenberg 1933KR86 |--N. t. tauriKR86 |--N. t. carniolicus Sket 1960KR86 |--N. t. jurinaci Karaman 1950KR86 |--N. t. kragujevensis Karaman 1950KR86 |--N. t. medvednicae Karaman 1950KR86 |--N. t. osogovensis Karaman 1959KR86 `--N. t. pecarensis Karaman & Karaman 1959KR86 N. tauricus Birstein 1964KR86 N. tenuicaudatus Schellenberg 1940KR86 N. thienemanni Schellenberg 1934KR86 N. toplicensis Andreev 1966KR86 N. transitivus Sket 1971KR86 |--N. t. transitivusKR86 `--N. t. dissonus Karaman 1984KR86 N. transsylvanicus Schellenberg 1934KR86 N. trullipes Sket 1958KR86 N. vadimi Birstein 1961KR86 N. valachicus Dobreanu & Manolache 1933KR86 N. vandeli Barbé 1961KR86 N. velesensis Karaman 1943KR86 N. virei Chevreux 1896KR86 N. vjeternicensis Karaman 1932KR86 |--N. v. vjeternicensisKR86 `--N. v. kusceri Karaman 1950 [incl. N. vjeternicensis kusceri f. bilecanus Karaman 1953]KR86 N. vodnensis Karaman 1943KR86 |--N. v. vodnensisKR86 |--N. v. banjanus Karaman 1943KR86 `--N. v. kosanini Karaman 1943KR86 N. vranjinae Karaman 1967KR86 N. wolfi Schellenberg 1933KR86 N. zavalanus Karaman 1950KR86 N. zorae Karaman 1967KR86
Niphargus pancici pancici Karaman 1929 [incl. N. pancici f. jakupicae Karaman 1960, N. pancici f. peristerica Karaman 1960, N. pancici f. prespensis Karaman 1960]KR86
Niphargus tatrensis Wrzesniowsky 1888 [incl. N. tatrensis f. aggtelekiensis Dudich 1932, N. tatrensis f. lunzensis Schellenberg 1935, N. tatrensis f. lurensis Schellenberg 1935, N. tatrensis f. otscherensis Schellenberg 1935, N. tatrensis f. reyersdorfensis Schellenberg 1935, N. tatrensis f. salzburgensis Schellenberg 1935, N. tatrensis f. schneebergensis Schellenberg 1935]KR86
*Type species of generic name indicated
References
[B77] Bousfield, E. L. 1977. A new look at the systematics of gammaroidean amphipods of the world. Crustaceana Suppl. 4: 282–316.
Fišer, C., B. Sket & P. Trontelj. 2008. A phylogenetic perspective on 160 years of troubled taxonomy of Niphargus (Crustacea: Amphipoda). Zoologica Scripta 37 (6): 665–680.
Fišer, Ž., F. Altermatt, V. Zakšek, T. Knapič & C. Fišer. 2015. Morphologically cryptic amphipod species are “ecological clones” at regional but not at local scale: a case study of four Niphargus species. PLoS One 10 (7): e0134384.
Flot, J.-F., G. Wörheide & S. Dattagupta. 2010. Unsuspected diversity of Niphargus amphipods in the chemoautotrophic cave ecosystem of Frasassi, central Italy. BMC Evolutionary Biology 10: 171.
[KR86] Karaman, G. S., & S. Ruffo. 1986. Amphipoda: Niphargus-group (Niphargidae sensu Bousfield, 1982). In: Botosaneanu, L. (ed.) Stygofauna Mundi: A Faunistic, Distributional, and Ecological Synthesis of the World Fauna inhabiting Subterranean Waters (including the Marine Interstitial) pp. 514–534. E. J. Brill/Dr W. Backhuys: Leiden.
Is it likely that such crypticism is the norm, so that the 300 known species should be more like a thousand (plus however many have escaped human attention altogether)?
I'm, incidentally, having trouble commenting here again. Right now it apparently works from my job computer, but not my private one.
I'd have no idea how widespread the crypsis is likely to be. The more epigean species may be genuinely widespread because they disperse more readily, but cryptic species may well be the norm among the hypogean taxa that make up the bulk of the population.
I don't know what would be happening with the comments. There's been some indications of background tinkering going on with Blogger recently; my own notifications of new comments disappeared for a while there. Does clearing your browser history help?