{{Short description|Genus of barnacles}} {{Speciesbox | genus = Rehderella | species = belyaevi | parent_authority = {{nowrap|Foster & Newman, 1987}}<ref name=FN87/>{{rp|327}} | authority = (Zevina & Kurshakova, 1973)<ref name=Z&K73>{{cite journal|last=Zevina|first=G. B.|author2=Kurshakova, T. S. |title=Addition to the fauna of Chthamalidae, Cirripedia of south-east Pacific|journal=Kompleksnye Issledovaniya Prirody Okeana|year=1973|volume=4|pages=183–189}}</ref> }}

'''''Rehderella''''' is an unusual and monotypic barnacle genus restricted to Easter Island and Pitcairn Island. '''''Rehderella belyaevi''''' is its only species.

Two other barnacle species are found in the intertidal zone of these islands. ''Euraphia devaneyi'' is much larger, and possesses calcareous basis. ''Tesseropora'' sp. has four shell plates with a single row of pores in shell wall. Both ''Euraphia'' and '''''Rehderella''''' have six shell wall plates. '''''Rehderella''''' differs from both in its membraneous basis and fusion of opercular plates on each side.

''Nesochthamalus intertextus'' is the only other Pacific Ocean barnacle with fused opercular plates. ''Nesochthamalus'' possesses a partially calcareous saucer-shaped basis, and fused opercular plates which show no visible trace of former articulation. '''''Rehderella''''' shows a line at the former articulation.

== Diagnosis and discussion == Shell wall of six plates with membraneous basis, and no basal infolding of shell wall. Sutures between wall plates are straight, and do not fuse at any time during its life cycle. The animal is small, about 5&nbsp;mm length, and flattened, with a pinkish-yellow color.<ref name=OP06/>{{rp|85}}

Opercular plates of '''''Rehderella''''' are distinctive in the scutum and tergum of each side fusing in young stages. A slight step in basal margin marks the former articulation between plates. Scutal adductor scar is deep and narrow, depressor pit indistinct. Tergal depressor crests 6-8, distinct, depending from basal margin.<ref name=FN87/>{{rp|327}}<ref name=OP06/>{{rp|85}}

Soft part distinctions include card setae on cirri develop only after animal reaches a size of 5&nbsp;mm.<ref name= FN87/>{{rp|328}} Caudal appendages are present, growing longer with age, up to 20 segments in large specimens.<ref name=FN87/>{{rp|330}}

=== Synonymy and nomenclature ===

==== ''Rehderella'' ==== * '''''Rehderella''''' {{aut|Foster & Newman}}, 1987: 327;<ref name=FN87>{{cite journal |author=Brian A. Foster & William A. Newman |year=1987 |title=Chthamalid Barnacles of Easter Island. Peripheral Pacific Isolation of Notochthamalinae new-subfamily and Hembeli group of Euraphiinae (Cirripedia: Chthamaloidea). |journal=Bulletin of Marine Science |volume=41 |issue=2 |pages=322–336 |url=http://www.ingentaconnect.com/content/umrsmas/bullmar/1987/00000041/00000002/art00020}}</ref> (original description): {{aut|Poltarukha}}, 2006: 85;<ref name=OP06>{{cite book|last=Poltarukha|first=O. P.|title=Identification Atlas of Superfamily Chthamaloidea (Cirripedia Thoracica) barnacles in World Ocean|year=2006|publisher=KMK Scientific Press, Ltd.|location=Moscow|isbn=5-87317-278-1|pages=1–198 [In Russian]}}</ref> (discussion). * Type species: ''Chthamalus belyaevi'' {{aut|Zevina & Kurshakova}}, 1973: 187 by original designation.

==== ''Rehderella belyaevi'' ==== * ''Chthamalus belyaevi'' {{aut|Zevina & Kurshakova}}, 1973: 187;<ref name=Z&K73/> (original description): {{aut|Newman & Ross}}, 1976: [https://www.biodiversitylibrary.org/page/4328584 41]; (summary of references). * ''Rehderella belyaevi'' ({{aut|Zevina & Kurshakova}}). {{aut|Foster & Newman}}, 1987: 327;<ref name=FN87/> (generic reassignment): {{aut|Poltarukha}}, 1996: 993;<ref name=OP96>{{cite journal|last=Poltarukha|first=O. P.|title=Composition, phylogeny and position in system of subfamily Notochthamalinae (Crustacea, Chthamalidae)|journal=Zoologicheskii Zhurnal|year=1996|volume=75|issue=7|pages=985–994|issn=0044-5134}}</ref> (discussion: 2006: 85;<ref name="OP06"/> (supplementary description, discussion). * Type locality: Easter Island. * Types and Repository: Zoological Museum, Moscow State University:<ref name=OP06/>{{rp|85}} Foster & Newman's topotypes; USNM 233268, 233269; British Museum (Natural History) Reg. No. 1987-3.<ref name=FN87/>{{rp|327}}

== Habitat and geographical range == This species is found only on Pitcairn Island and Easter Island in the uppermost intertidal and surf zone, where it forms dense colonies. Whelk predation sets lower environmental limits. During times of calm seas, colonies can be exposed to air and sun for extended periods.<ref name=FN87/>{{rp|330}} In this upper zone, dominance is shared by the gastropod ''Nodolittorina pyramidalis pascua'', an algal grazer. Near the base of the barnacle zone, another grazer, ''Nerita morio'' becomes more common, along with other fauna.<ref>{{cite journal|last=Osorio|first=C|author2=V. Cantuarias |title=Vertical Distribution of Mollusks on the Rocky Intertidal of Easter Island|journal=Pacific Science|year=1989|volume=43|issue=4|pages=302–315|issn=1534-6188}}</ref>{{rp|306}}

== References == {{Reflist|32em}}

== External links == {{Wikispecies-inline}} * [http://marinespecies.org/aphia.php?p=taxdetails&id=733083 WoRMS]

{{Taxonbar|from1=Q16989036|from2=Q21309886}}

Category:Barnacles Category:Monotypic Maxillopoda genera