A NEW SPECIES OF PATIRIELLA 



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a 



b 



Fig. 3 a, Photograph of Patiriella paradoxa, Holotype. from Wadi Haart. Sadh. Dhofar, Southern Oman. Abactinial view. Scale in mm; b. Photograph of 

 Patiriella paradoxa, Holotype, from Wadi Haart, Sadh, Dhofar, Southern Oman. Actinial view. Scale in mm. 



furrows occurring between the oblique lines of plates. First com- 

 plete oblique line of plates arises opposite the second adambulacral 

 plate in each furrow, creating a triangular area bounded by the first 

 adambulacral plates, distal edge of the oral plates and first oblique 

 series in each actinal intermediate area. This proximal area occupied 

 by 2 (interradii BC, DEandEA), 3 (interradiusAB)or4(interradius 

 CD) plates. A small circular patch of non-calcified skin (up to 

 0.6mm diameter) occurring adjacent to the distal edge of the oral 

 plates in interradii AB, CD and E A. Actinal plates each bear a single, 

 tapering spinelet (up to 0.64mm long x 0.30mm at base) on the 

 proximal 80% of the actinal surface, the remaining distal plates with 

 2 small spinelets. 



There are 28-29 pairs of adambulacral plates to each furrow. 

 These are twice as wide as long. First 12-14 plates bear 2 tapering 

 furrow spines, proximalmost more slender and shorter than distalmost 

 spine (on adambulacral 3: distalmost spine measures 1.0mm long x 

 0.35mm wide, at base tapering 0.20mm wide near tip; proximalmost 

 spine measures 0.78mm long x 0.23mm wide at base, tapering to 

 0. 14mm wide near tip). Proximalmost spine becomes rapidly smaller 

 and peg-like towards the 12th— 14th plate, beyond which the 

 adambulacral plates each bear a single furrow spine. A single, 

 stouter, subambulacral spine (on adambulacral 3: 0.87mm long x 

 0.29mm wide, more or less cylindrical) occurs on each adambulacral 

 plate. The oral plates each with 4 oral (furrow) spines of which the 

 apicalmost is longest. No suboral spines. 



Gonopores not occurring on the oral surface and cannot be 

 distinguished aborally. 



COLOUR. Dried holotype is a uniform, pale 'museum' buff colour. 

 Colour in life is not recorded. 



Paratype 1. BMNH 1997.1017 has R=19.0mm, r=7.9mm. 



R/r=2.4; br=9.4mm, R/br=c.2. Generally very similar in appearance 

 to the holotype, differing only in minor detail. Two furrow spines 

 occurring only on the 1 st— 4th adambulacral plates, thereafter the 

 plates with a single furrow spine. Small patch of non-calcified skin 

 occurs adjacent to the distal edge of the oral plates in each interradius, 

 this proximal actinal triangle being filled by 1 (interradii CD, DE) or 

 2 (interradii EA, AB, BC) plates. 



Paratype 2. BMNH 1997.1018 has R=19.0mm, r=10.00mm, 

 R/r=1.9; br=l 1.2 mm, R/br=1.7. The dry specimen is contorted. It 

 differs from the holotype and paratype 1 in the following features. 

 Rays are slightly broader at their bases relative to their lengths. 

 Aborally, centre of disc not delimited by a prominent ring or rings of 

 plates. Radial 'field' of abactinal plates is compact, plates closely 

 imbricating with only the ridge evident and bearing 5-7 spinelets. 

 Papular areas contain 1-4 papulae and occasionally a single second- 

 ary plate. Actinal spinulation coarser, otherwise the plate arrangement 

 closely similar to the other type specimens. Actinal proximal trian- 

 gle filled by 1 or 2 plates, no patches of non-calcified skin evident. 

 Some 36 pairs of adambulacral plates along each furrow; each 

 bearing a single furrow and single subambulacral spine, with the 

 exception of the first plate with a second, smaller proximal furrow 

 spine. Furrow and subambulacral spines flattened along their length 

 with a squared-off tip. Several furrow spines spaced along length of 

 the furrow, with bifid tip. Oral plates and spines are similar to those 

 of both the holotype and paratype 1 . The paratype 2 is uniformly 

 light grey in colour. 



HABITAT. The holotype and paratype 1 were collected on 4.5.87, 

 0.5km. south east of Wadi Haart and about 4 km. north east of Sadh 

 village. These were collected, together with 'Asterina' cepheus 

 intertidally on a gently shelving exposed rocky shore with tide pools 

 just below the level of the conspicous barnacle Tetraclita squamosa 



