Tag Archives: Rapa Nui

Curculionidae gen. & sp. ‘Rapa Nui’

Smaller Rapa Nui Cossonine Weevil (Curculionidae gen. & sp.)

The Smaller Rapa Nui Cossonine Weevil is one of two new weevil species that were recorded from core samples that were collected from the lake in the Rano Kau volcano on Rapa Nui.

The species is known from four heads, six prothoraces, 13 elytra and two first two-fused ventrites, it reached an estimated size of about 0,25 to 0,29 cm. [1]

The species is now extinct.

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References:

[1] M. Horrocks; M. Marra; W. T. Baisden; J. Flenley; D. Feek; L. González Nualart; S. Haoa-Cardinali; T. Edmunds Gorman: Pollen, phytoliths, arthropods and high-resolution 14C sampling from Rano Kau, Easter Island: evidence for late Quaternary environments, ant (Formicidae) distributions and human activity. Journal of Paleolimnology 50(4): 417-432. 2013

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edited: 10.12.2018

Curculionidae gen. & sp. ‘Rapa Nui’

Rapa Nui Molytine Weevil (Curculionidae gen. & sp.)

The Rapa Nui Molytine Weevil (family Curculionidae: subfamily Molytinae) is known from numerous body parts that were recovered from core samples made in the lake in the crater of the Rano Raraku volcano on Rapa Nui. [1]

The species is known exclusively from these samples of Holocene age and is clearly extinct.

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References:

[1] N. Cañellas-Boltà; V. Rull; A. Sáez; O. Margalef; S. Giralt; J. J. Pueyo; H. H. Birks; H. J. B. Birks; S. Pla-Rabes: Macrofossils in Raraku Lake (Easter Island) integrated with sedimentary and geochemical records: towards a palaeoecological synthesis for the last 34,000 years. Quaternary Science Reviews 34: 113-126. 2012

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edited: 10.12.2018

Elaeocarpus sp. ‘Rapa Nui’

Rapa Nui Elaeocarpus (Elaeocarpus sp.)

This taxon is known from wooden remains collected near the Ahu Akahanga at the southern coast of Rapa Nui, it most certainly was an endemic species, which is now extinct. [1]

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References:

[1] Catherine Orliac: Données nouvelles sur la composition de la flore de l’île de Pâques. Journal de la Société des Océanistes 107: 135-143. 1998

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edited: 11.12.2018

Potamogeton sp. ‘Rapa Nui’

Rapa Nui Poondweed (Potamogeton sp.)

This taxon appears in lists of endemic plants that once inhabited Rapa Nui, it is known from pollen findings.

These pollen, however, appear to be at least 16600 years old, so are pre-Holocene of age; unfortunately, I have no idea how long this taxon may have survived on the island, thus it is mentioned here just for the sake of completeness.

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References:

[1] J. R. Flenley; Sarah M. King: Late Quaternary pollen records from Easter Island. Nature 307(5): 47-50. 1984
[2] Catherine Orliac: Données nouvelles sur la composition de la flore de l’île de Pâques. Journal de la Société des Océanistes  107: 135-143. 1998
[3] Anthony Dubois; Pierre Lenne; Elsa Nahoe; Marcos Rauch: Plantas de Rapa Nui. Guía Ilustrada de la Flora de Interés Ecológico y Patrimonial. Umanga mo te Natura, CONAF, ONF International, Santiago 2013

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edited: 13.11.2021

Metrosideros sp. ‘Rapa Nui’

Rapa Nui Ironwood (Metrosideros sp.)

The genus Metrosideros is known from Rapa Nui based on subfossil pollen. [1]

These pollen either came from a former indigenous population of the rather widespread Polynesian Ironwood (Metrosideros collina (J. R. Forst. & G. Forst.) A. Gray) or, given the isolated situation of Easter Island, more likely from an endemic species.

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References:

[1] J. R. Flenley; A. Sarah M. King; Joan Jackson; C. Chew: The Late Quaternary vegetational and climatic history of Easter Island. Journal of Quaternary Science 6(2): 85-115. 1991

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edited: 11.12.2018

Chironomus sp. ‘Rapa Nui’

Rapa Nui Nonbiting Midge (Chironomus sp.)

The Rapa Nui Nonbiting Midge is known from a single larva specimen that was found in a core sample that was collected in the lake of the Rano Kau volcano crater on Rapa Nui at a depth of about 10,9 to 11 m. [1]

The genus may still occur on Rapa Nui today, but not this particular species, because nearly all vertebrates and invertebrates found on the island today, were introduced, mostly in quite recent times.

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References:

[1] M. Horrocks; M. Marra; W. T. Baisden; J. Flenley; D. Feek; L. González Nualart; S. Haoa-Cardinali; T. Edmunds Gorman: Pollen, phytoliths, arthropods and high-resolution 14C sampling from Rano Kau, Easter Island: evidence for late Quaternary environments, ant (Formicidae) distributions and human activity. Journal of Paleolimnology 50(4): 417-432. 2013

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edited: 10.12.2018

Nesopupa sp. ‘Rapa Nui’

Rapa Nui Nesopupa Snail (Nesopupa sp.)  

This snail is known from a single specimen that was collected in 1991 during excavations at Anakena at the north coast of Rapa Nui. [1]

The Rapa Nui taxon was certainly an endemic species that is now extinct. 

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References: 

[1] Patrick V. Kirch; Carl C. Christensen; David W. Steadman: Subfossil Land Snails from Easter Island, Including Hotumatua anakenana, New Genus and Species (Pulmonata: Achatinellidae). Pacific Science, 63: 105–122. 2009

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edited: 11.12.2018

Dianella sp. ‘Rapa Nui’

Rapa Nui Flax Lilly (Dianella sp.)

This taxon is known from macro-and microfossils that were found in core samples collected in the crater of the Rano Raraku on Rapa Nui, which can be dated to an age of about 9400 to 5400 BCE, which means, that they apparently disappeared prior to the first Polynesian settlement. [1]

The taxon may have been the widespread Polynesian Flax Lilly (Dianella adenanthera (G. Forst.) R. J. F. Hend.) (see photo below) or an endemic species.

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References:

[1] N. Canellas-Bolta; V. Rull; A. Saez; M. Prebble; O. Margalef: First records and potential palaeoecological significance of Dianella (Xanthorrhoeaceae), an extinct representative of the native flora of Rapa Nui (Easter Island). Vegetation History and archaeobotany 23(3): 331-338. 2014

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Photo: Peter de Lange 
http://www.inaturalist.org/people/pjd1

(public domain)

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edited: 11.12.2018

Helicinidae gen. & sp. ‘Rapa Nui’

Rapa Nui Helicinid Land Snail (Helicinidae gen. & sp.)  

This taxon is known so far only from a single apical fragment of a shell that was found during excavations at Anakena at the north coast of Rapa Nui in 1991.

Despite its fragmented character it could at least be assigned to the family Helicinidae which is widely distributed in the Pacific region, occuring on all higher islands. [1]

The Rapa Nui Helicinid Land Snail was certainly endemic to the island.

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References: 

[1] Patrick V. Kirch; Carl C. Christensen; David W. Steadman: Subfossil Land Snails from Easter Island, Including Hotumatua anakenana, New Genus and Species (Pulmonata: Achatinellidae). Pacific Science, 63: 105–122. 2009

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edited: 11.12.2018

Allodessus skottsbergii (Zimmerman)

Skottsberg’s Diving Beetle (Allodessus skottsbergi)  

Skottsberg’s Diving Beetle was described in 1924, it is known only from the island of Rapa Nui.

The species reaches a body length of about 0,2 to 0,23 cm and is yellowish to ferruginous colored, males and females are superficially identical.  

The beetle inhabits the crater lakes of Rapa Nui, where it lives among algae, it is a predacious species. [1][2]  

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The beetle is known already from subfossil core samples, where its remains can be found at a depth of about 15,5 m, in sediments that were deposited before the first Polynesian settlers appeared, which means that the species indeed is at least native to Rapa Nui, perhaps even endemic. [4]

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Skottsberg’s Diving Beetle was apparently not recorded during recent field studies and may in fact already join the list of extinct species. [3]

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References:  

[1] A. Zimmermann: Coeloptera-Dytiscidae von Juan Fernandez und der Osterinsel. in The Natural history of Juan Fernandez and Easter Island, edited by Carl Skottsberg. Vol. 3: 299-304., Zoology. Uppsala: Almqvist & Wiksells Boktryckeri, 1921-1940 
[2] Michael Balke; Ignacio Ribera: Jumping across Wallace’s line: Allodessus Guignot and Limbodessus Guignot revisited (Coleoptera: Dytiscidae, Bidessini) based on molecular-phylogenetic and morphological data. Australian Journal of Entomology 43(2): 114-128. 2004  
[3] Konjev Desender; Léon Baert: The Coleoptera of Easter Island. Bulletin de l’Institut royal des Sciences naturelles de Belgique. Entomologie 66: 27-50.1996
[4] M. Horrocks; M. Marra; W. T. Baisden; J. Flenley; D. Feek; L. González Nualart; S. Haoa-Cardinali; T. Edmunds Gorman: Pollen, phytoliths, arthropods and high-resolution 14C sampling from Rano Kau, Easter Island: evidence for late Quaternary environments, ant (Formicidae) distributions and human activity. Journal of Paleolimnology 50(4): 417-432. 2013

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edited: 11.12.2018

Curculionidae gen. & sp. ‘Rapa Nui’

Larger Rapa Nui Cossine Weevil (Curculionidae gen. & sp.)

The Larger Rapa Nui Cossine Weevil is one of two weevils from the subfamily Cossoninae that was found in core samples that were collected from the lake of the Rano Kau volcano on Rapa Nui.

The species is known from 7 heads, two prothoraces, 15 elytra, one meso/metasternum, and one abdomen base, it reached an estimated size of about 0,34 to 0,36 cm. [1]

The species is now extinct.

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References:

[1] M. Horrocks; M. Marra; W. T. Baisden; J. Flenley; D. Feek; L. González Nualart; S. Haoa-Cardinali; T. Edmunds Gorman: Pollen, phytoliths, arthropods and high-resolution 14C sampling from Rano Kau, Easter Island: evidence for late Quaternary environments, ant (Formicidae) distributions and human activity. Journal of Paleolimnology 50(4): 417-432. 2013

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edited: 10.12.2018

Orobatida gen. & sp. ‘Rapa Nui’

Rapa Nui Beetle Mite (Orobatida gen. & sp.)

This species is known from core samples that were collected from the lake in the Rano Kau volcano on Rapa Nui, it is known from three samples from depths of 11,05 to 10,3 m. [1]

The species appears to be extinct now.

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References:

[1] M. Horrocks; M. Marra; W. T. Baisden; J. Flenley; D. Feek; L. González Nualart; S. Haoa-Cardinali; T. Edmunds Gorman: Pollen, phytoliths, arthropods and high-resolution 14C sampling from Rano Kau, Easter Island: evidence for late Quaternary environments, ant (Formicidae) distributions and human activity. Journal of Paleolimnology 50(4): 417-432. 2013

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edited: 10.12.2018

Premna sp. ‘Rapa Nui’

Rapa Nui Headache Tree (Premna sp.)

The Headache Tree (Premna serratifolia L.) is a Indopacific species, that means it is widely distributed all along the Indian – as well as the Pacific Ocean including the Pitcairn Islands, the region closest to Rapa Nui, mainly occurs in littoral forests. Thus, it is quite possible that this particular species also inhabited Rapa Nui.

However, the genus has apparently also given rise to at least one endemic species in the Polynesian region, the Avaro (Premna tahitensis Schauer), which is either an endemic Tahitian species or simply a synonym of the other widespread species, a revision of the taxonomy of this genus is still pending.

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The Rapa Nui form is known from charcoal remains, it might have been identical to the widespread form or might have been an endemic one, now extinct. [1]

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References:

[1] Terry L. Hunt: Rethinking Easter Island’s ecological catastrophe. Journal of Archaeological Science 34: 485-502. 2007

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edited: 22.06.2020

Psittacidae gen. & sp. ‘Rapa Nui’

Rapa Nui Parrot (Psittacidae gen. & sp.)

Parrots are represented by a partial quadrate of a very large species (larger than in Nestor, Prosopeia, Eclectus, or any lorikeet; dissimilar from that in neotropical parrots) and digit I, phalanx 2 of the wing (larger than in Vini or Cyanoramphus, smaller than in Nestor or Eclectus; ca. the size in Prosopeia).” [1]

It is usually thought that the island formerly was inhabited by two species of parrots, however, I personally think that this might well have been a single one, a large parrot with very reduced wings.

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References:

[1] David W. Steadman: Extinction and Biogeography of Tropical Pacific Birds. University of Chicago Press 2006

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Depiction by Alexander Lang

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edited: 22.06.2020

Myrsine sp. ‘Rapa Nui’

Rapa Nui Myrsine (Myrsine sp.)

This form is known from charcoal remains that were recovered from deposits on Easter Island. [1]

The genus Myrsine contains an unknown [to me] number of species, with at least 70 species, subspecies and varieties occurring in the Polynesian region. The closest place to Rapa Nui still harboring endemic species are the Pitcairn Islands, which are the home of two endemic species, Hosaka’s Myrsine (Myrsine hosakae H. St. John) on Henderson Island as well as a still undescribed [?] species on Pitcairn Island. 

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References:

[1] Terry L. Hunt: Rethinking Easter Island’s ecological catastrophe. Journal of Archaeological Science 34: 485-502. 2007

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edited: 22.06.2020

Santalum sp. ‘Rapa Nui’

Rapa Nui Sandalwood (Santalum sp.)  

The Rapa Nui Sandalwood is actually a hypothetical species, it is apparently known only from oral tradition.  

The plant was known to the Polynesian inhabitants as “naunau” or “nau opata“.  

The fruits are said to have been eaten, the emty nutshells were used by children as toys, the scent of the stem was described as very strong and perfuming.  

The species is considered extinct on the island since 1895. [1]  

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References:  

[1] Anthony Dubois; Pierre Lenne; Elsa Nahoe; Marcos Rauch: Plantas de Rapa Nui. Guía Ilustrada de la Flora de Interés Ecológico y Patrimonial. Umanga mo te Natura, CONAF, ONF International, Santiago 2013  

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edited: 04.09.2019

Zapornia sp. ‘Rapa Nui’

Rapa Nui Crake (Zapornia sp.)  

This species, hitherto not described, is known only on the basis of a single bone, a tibiotarsus, which, however, can unequivocally be assigned to the genus Zapornia.  

The Rapa Nui Crake was much smaller than the widespread Spotless Crake (Zapornia tabuensis (Gmelin)), in fact it was among the smallest rail species known, very similar to some of the Hawaiian species, and was very possibly flightless.  

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References:  

[1] D. W. Steadman: Extinction and Biogeography of Tropical Pacific Birds. University of Chicago Press 2006  

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edited: 20.09.2017

Trema sp. ‘Rapa Nui’

Rapa Nui Nettletree (Trema sp.)  

The genus Trema is in need of a review.  By all means, subfossil pollen, found in the sediments of the Rano Kau crater, shows that a species of this genus once grew on Easter Island.  

This pollen may belong to a neotropical species, e.g. the Jamaican Nettletree (Trema micrantha (L.) Blume), or may come from the extant Pale Nettletree (Trema discolor (Brongniart) Blume), a plant that still occurs in some places within Polynesia today, or, most probably, from an endemic and therefore extinct species.  

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edited: 23.03.2018

Tetragnatha paschae Berland

Rapa Nui Long-legged Spider (Tetragnatha paschae)  

This enigmatic species was described in 1924 based on three (?) female specimens – no one has ever found similar spiders on Easter Island since.

Rosemay G. Gillespie, who is an expert for spiders, especially of the genus Tetragnatha, considered is possibly identical to the Large Long-legged Spider (Tetragnatha maxillosa Thorell) which originates from Asia and is now distributed almost worldwide. This species, however, could not be recorded during fieldstudies which took place in 2012, instead the Brown Long-legged Spider (Tetragnatha nitens (Audouin)), a species that originates from the Mediterranean, was found.

If the Rapa Nui Long-legged Spider turns out to have indeed been a distinct, endemic species, it is now most certainly extinct. [1] 

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References:  

[1] Darko Davor Cotoras Viedma: Colonization of the most isolated island on Earth: What is the origin of the spider Tetragnatha paschae? 2012  

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prosoma and left jaw claw  

Depiction from: ‘L. Berland: Araignées de l’ile de Pàques et des iles Juan Fernandez. In: Skottsberg, C. (Ed.): The Natural History of Juan Fernandez and Easter Island 3: 419-437. 1924’  

(not in copyright)

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edited: 31.10.2016

Hotumatua anakenana Kirch, Christensen & Steadman

Hotu Matua’s Snail (Hotumatua anakenana)   

This tiny snail species (shell height ca. 0,42 cm) was described in 2009 based on subfossil shells that were found during excavations at Anakena on the north coast of Rapa Nui.  

Hotu Matua’s Snail disappeared after the complete destruction of the island’s indigenous vegetation and accompanied the loss of the microhabitats it inhabited.  

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The species was named after Hotu Matua, the mythical ancestor of the Rapa Nui people, the Polynesian inhabitans of Easter Island, as well as for Anakena Bay, the place where Hotu Matua is said to have first landed. [1]  

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The material that was collected included three additional specimens that are referable to the genus Hotumatua, but differ in some ways and are certainly not conspecific with the species discussed here. These shells are either intraspecific variations or distinct species, but more material is needed to determine either of these assumptions. [2]  

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Another tiny Achatinellid snail that was known from the island based on subfossil shells, the Variable Pacificella Snail (Pacificella variabilis Odhner) was recently rediscovered on Easter Island, it is, however, a Polynesian introduction and not native to the island. [2][3]  

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References:  

[1] John Flenley; Paul G. Bahn: The Enigmas of Easter Island. Oxford University Press (Oxford, New York) 2003 
[2] Patrick V. Kirch; Carl C. Christensen; David W. Steadman: Subfossil Land Snails from Easter Island, Including Hotumatua anakenana, New Genus and Species (Pulmonata: Achatinellidae). Pacific Science, 63: 105–122. 2009 
[3] Juan Francisco Araya; Juan Antonio Aliagoa; Darko D. Cotoras: Rediscovery of Pacificella variabilis (Gastropoda: Achatinellidae) on Easter Island. Pacific Science 72(4): 1-13. 2017  

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edited: 11.12.2018