Functional morphology of the Ordovician plectambonitoid brachiopod Inversella (Reinversella) arancibiai Herrera & Benedetto from the San Juan Formation, Argentine Precordillera

被引:4
作者
Benedetto, Juan L. [1 ]
Sorrentino, Leonor [2 ]
Cech, Norma [1 ]
Sanchez, Teresa M. [1 ]
机构
[1] Univ Nacl Cordoba, Fac Ciencias Exactas Fis & Nat, Ctr Invest Paleobiol, CONICET, RA-5000 Cordoba, Argentina
[2] Monash Univ, Sch Geosci, Clayton, Vic 3800, Australia
来源
ALCHERINGA | 2008年 / 32卷 / 01期
关键词
brachiopod; Ordovician; Argentina; precordillera; functional morphology;
D O I
10.1080/03115510701757373
中图分类号
Q91 [古生物学];
学科分类号
0709 ; 070903 ;
摘要
New well-preserved material of the plectambonitoid brachiopod Inversella (Reinversella) arancibiai Herrera Benedetto, 1987 collected from the San Juan Formation (Darriwilian, Middle Ordovician) of the Argentine Precordillera is described and illustrated, allowing a better understanding of its functional morphology. Inversella (Reinversella) is one of the earliest known brachiopods to develop a geniculate shell. Adult specimens of I. (R.) arancibiai have an open delthyrium indicating attachment throughout life. We infer that juvenile specimens lacking geniculation lived umbo-down and that development of geniculation could reflect a progressive change in mode of life from erect to reclined. The posterior thickening of valves indicates a life position with the umbonal region sunk in the substrate and the trail orientated in a subvertical position. Since open shelf settings inhabited by I. (R.) arancibiai have low sedimentation rates, it seems improbable that geniculation was an adaptation to counter shell burial. Its function was most probably to separate exhalant and inhalant currents. We hypothesize that the deep channel developed along the periphery of the ventral valve functioned as a collector of waste waters towards the posterolateral regions of the shell where exhalant currents were expelled.
引用
收藏
页码:53 / 63
页数:11
相关论文
共 44 条
[1]  
Albanesi Guillermo L., 2002, Serie Correlacion Geologica, V16, P143
[2]  
[Anonymous], MINERAL CONCHOLOGY G
[3]  
[Anonymous], 1828, KUNGLIGA SVENSKA VET
[4]  
Bancroft B. B., 1929, Memoirs of the Manchester Literary and Philosophical Society, V73, P33
[5]  
BASSETT MG, 1984, SP PAP PALAEONTOL, P237
[6]  
Bates D. E. B., 1968, B BRIT MUS NAT HIST, V16, P127
[7]  
Benedetto J.L., 2003, Ordovician fossils of Argentina. Secretaria de Ciencias y Tecnologia
[8]  
BENEDETTO JL, 2002, ASPECTS ORDOVICIAN S, V16, P87
[9]  
BRUSSA ED, 2003, INSUGEO SERIE CORREL, V18, P21
[10]  
Canas F., 2003, ORDOVICIAN FOSSILS A, P131