FROM WEST PAKISTAN 47 



Hermanites palmatus sp. nov. 



(Plate 24, figs. 1-9, ii, 12) 



Derivation of name. Latin palmatus, palmate ; with reference to the palmate 

 appearance of the ridges in front of the subcentral-tubercle. 



Diagnosis. Hermanites in which dorsal and ventral ridges are alate and joined 

 posteriorly by a transverse ridge which is slightly concave towards posterior. Sub- 

 central-tubercle prominent with palmate appearance of ridges in front. 



Holotype. Io. 4337, a female left valve (PI. 24, figs. 6, 8, 9, 11). 



Paratypes. Io. 4286 + Io. 3117-8. 



Material. 9 specimens from the Rakhi Nala section from five horizons (sample 

 nos. 3613 to 3615, 3617 and 3618). 17 specimens from the Zao River section from 

 four horizons (sample nos. 24131, 24150, 24152 and 24156). GSP BM 2554-5. 



Type locality. Zao River section. 



Type horizon. Upper Chocolate Clays, sample no. 24152. 



Description. Sexual dimorphism apparent ; the females being shorter than the 

 males. Carapace subrectangular in lateral outline with greatest height in the region 

 of the anterior cardinal angle. Dorsal and ventral margins almost straight, anterior 

 margin broadly rounded, posterodorsal corner very slightly concave, posterior 

 extremity and posteroventral margin rounded. Valves almost equal. Subcentral- 

 tubercle prominent. Eye-tubercle rounded and distinct. Surface recticulate with 

 alate dorsal and ventral ridges which are joined posteriorly by a transverse ridge 

 which is slightly concave towards the posterior. Anterior and posterior marginal 

 platforms compressed. Anterior and posterior marginal rims distinct. Anterior 

 margin ornamented with 20-25 small spines, posterior with 6-8 larger spines. 

 Duplicature of moderate width, 0-050 mm. anteriorly. Both valves have a distinct 

 selvage. Hinge holamphidont : left valve hinge with fairly deep anterior socket, 

 anteromedian tooth rounded, subcorneal (slightly projecting towards the anterior in 

 dorsal view), posteromedian ridge denticulate and deep, slightly elongate posterior 

 socket ; right valve hinge with anterior subcorneal, projecting tooth followed by deep 

 postjacent socket, posteromedian shallow groove and an almost rounded, posterior 

 tooth. 



Dimensions (mm). 



Io. 4286 

 Io. 3117 

 Io. 4337 

 I0.3118 



Comparison. Hermanites scopus sp. nov. is larger, has a curved ventral ridge and 

 subtriangular posterior margin. Hermanites indicus Tewari and Tandon (i960) has 

 a subtriangular posterior end and lacks the transverse ridge which posteriorly joins 

 the dorsal and ventral ridges. The Miocene species Hermanites purii Tewari and 

 Tandon (i960) has somewhat similar lateral outline, but lacks both the transverse 





L 



H 



w 



Carapace male 



0-69 



o-37 



o-37 



Carapace female 



0-63 



o-37 



o-37 



Left valve female (holotype) 



0-73 



0-40 



— 



Left valve female 



073 



0-44 



— 



