Tetraclitella nodicostata, Buckeridge, John S., 2008

Buckeridge, John S., 2008, Two new species and a new subspecies of Tetraclitella (Cirripedia: Thoracica) from the Cainozoic of Australia and New Zealand and a consideration of the significance of tubiferous walls, Zootaxa 1897, pp. 43-52 : 47

Tetraclitella nodicostata sp. nov.

Figure 2 A,B

1983:? Tetraclitella sp. cf. T. purpurascens (Wood, 1815): Buckeridge, 77–78.

Diagnosis: Tetraclitella of low conic form; radii relatively narrow; small to medium diameter longitudinal pores in paries; parietes externally with strong apico-basal ribbing beaded by transverse growth lines.

Distribution and age: Northern New Zealand. Early Miocene.

Holotype: A177, a latus from Pinehill Road, Waiotemarama Valley, Northland, New Zealand ( Figure 2 ).

Material: Otaua Mudstone: A177, a latus (holotype), length (exterior): 6.0mm, width (basal): 5.9mm; AU 5737: a further latus, from Pinehill Road, Waiotemarama Valley, Northland, New Zealand. Age: Early Miocene ( New Zealand Stratigraphic Stage: Waitakian-Otaian). ( NZ Fossil Record file number (metric) O 06/ f9642. NZMS 1:50,000 Grid Reference O 06/510285), collected by L. Wakefield on 31 December 1972.

Cape Rodney Formation: AU 10129, a single latus, (Waitakian-Otaian Age) Matheson’s Bay, North Auckland ( NZ Fossil Record File number R09/f9511), collected by P. F. Ballance. All specimens are held in the type collection of the Geology Department, University of Auckland, Auckland, New Zealand.

Description (based upon latera only): Shell small, moderately depressed conic, external ribbing pronounced, sinusoidal and bifurcating, beaded by transverse growth lines; parietes with numerous longitudinal tubes that are polyhedral in section, and which increase in diameter towards the sutural margins; radii relatively narrow, with small diameter interseptal tubes. Sheath weakly developed, but extending to almost half the length of paries in a lateral plate; base and opercula unknown.

Comments: No further material has been recovered since Buckeridge (1983). The redesignation of the material described as? Tetraclitella sp. cf. T. purpurascens (Wood, 1815) in Buckeridge (loc. cit.) follows a revision of shallow water Australasian sessile barnacles by Foster and Anderson (1986), wherein Tetraclitella purpurascens (Wood, 1815) , previously thought to have been found on both sides of the Tasman Sea, was shown to be restricted to Australia. The New Zealand taxon Tetraclitella depressa Foster and Anderson, 1986 , to which this form is most closely related, may be readily distinguished by its shell profile: T. depressa is very flat, has larger diameter parietal pores and less pronounced external longitudinal ribbing.

Etymology: Morphological, in allusion to the strong, nodose exterior ribbing on the paries (Latin: nodus = a knot; costa = ribs).

Figures

FIGURE 2. Tetraclitella nodicostata sp. nov. A: A 177 (holotype) – latus, showing prominent, nodular longitudinal ribbing and narrow radius (exterior); B: A 177 – latus, showing weakly developed sheath and honeycomb like parietal pores (interior). Specimen has been coated with polyvinyl acetate to prevent disintegration.