Conus kanayai           (Shuto, 1969)

 

 

Material.

Holotype: GK-L 6909 and paratype: GK-L 6908.

Holotype specimen  is  full-grown  and  almost  perfect  except  for  the  protoconch,  while the  paratype is broken  at  the  apex  and  labrum. They  came  from  one  and  same  locality.         

 

 

Measurements.

Specimen              H             Bd             D           Bd/H   D/H           ZP                  whorls

(mm)        (mm)         (mm)        (%)                 degrees     proto         teleo

6908                  99,4         81,5          31,50        81,9  31,7         57,4           -                9

6909                 114,1        95,2          40,95        83,4  35,9          72,5          1              12

 

Diαgnosia.

The  shell  is  large     solid     and  asymmetrically  biconical.  The  spire is  slightly  extraconical  with  the  tangential  angle  of  about  50  degrees  at  early  and more  than  70  degrees  at the  adult  whorls.  The  basal  cone  is  more  than  four times longer  than  the  spire  and  regularly  tapered  anteriorward.  The  protoconch  is  not known.  The  teleoconch  consists  of  about  twelve  whorls.  The  spire whorls  are rather  sharply  angulated  at  the  middle  of  the  whorl height the  surface  above the angulation  is  distinctly  concave  and  moderately  sloped     while  the  lateral  surface  is slightly  convex  and  inclined  outwardly.  The  early  whorls  are  provided  with  the distinct  nodules  at  the  peripheral  angulation.  They  are  rather  strong  and  not necessarily  confined  to the  angulation  but  extend  axially  giving  rise  to  the  oblique ribs  on  the  first third  whorls  and  thereafter  they  are  weakened  gradually.  In consequence  the  peripheral  angulation  is  almost  smooth  except  for  the  obsolete undulation  on  the  eighth  whorl.  A  distinct spiral  groove  is  discernible  at  some distance  below  the  suture  to  define  a  subsutural  lira  on  the first  whorl.  The subsutural  lira  is  overriden  by  the  coarse  and  somewhat  protractly  oblique growth  lines.  Between  the  infrasutural  groove  just  mentioned  and  the  peripheral angulation  are  intercalated  a  few  fine  grooves  one  by  one  on the  third  and  later whorls.  The  subsutural  lira  becomes  indistinct  and  subdivided  by  a  shallow groove  on  later  whorls.  A  few  fine  and  shallow  spiral  grooves  are  discernible  on the  lateral  surface  of  the  early  whorls     but  they  disappear  on  the  penultimate  one. The  grooves  above  the  peripheral  angulation  also  become  weak  on  the  penultimate and  quite  disappear  at  the  last  part  of  the  body  whorl  The  basal  fasciole  is strong  with  coarse  sculpture     which  is  reduced  upward  and  finally  disappears  at the  middle  of  the  basal  slope.

Diagnosis.-The shell is large, solid, and asymmetrically biconical. The spire is slightly extraconical with the tangential angle of about 50 degrees at early and more than 70 degrees at the adult whorls. The basal eone is more than four times longer than the spire and regularly tapered anteriorward. The protoconch is not known. The teleoconch consists of about twelve whorls. The spire-whorls are rather sharply angulated at the middle of the whorl-height; the surface above the angulation is distinctly concave and moderately sloped, while the lateral surface is slightly convex and inclined outwardly. The early whorls are provided with the distinct nodules at the peripheral angulation. They are rather strong and not necessarily confined to the angulation but extend axially giving rise to the oblique ribs on the first to third whorls and thereafter they are weakened gradually. In consequence the peripheral angulation is almost smooth except for the obsolete undulation on the eighth whorl. A distinct spirai groove is discernible at some distance below the suture to define a subsutural lira on the first whorl. The subsutural lira is overriden by the coarse and somewhat protractly oblique growth lines. Between the infrasutural groove just mentioned and the peripheral angulation are intercalated a few fine grooves one by one on the third and later whorls. The subsutural lira becomes indistinct and subdivided by a shallow groove on later whorls. A few fine and shallow spirai grooves are discernible on the lateral surface of the early whorls, but they disappear on the penultimate one. The grooves above the peripheral angulation also become weak on the penultimate and quite disappear at the last part of the body whorl. The basal fasciole is strong with coarse sculpture, which is reduced upward and finally disappears at the middle of the basal slope.

The  aperture  is  elongate  and  narrow  with  almost  parallel  lips     of  which  the inner  one  is  almost  straight     while  the  labrum  is  slightly  depressed  at  the  middle and  then  widened  anteriorly.  The  anterior  part  is  distinctly  bent  backward  and obliquely  truncated  at the  end.  The  anal  sinus  is  very  asymmetric  with the upper  arm  directly  converging  to  the  suture  with  the  angle  of  80  degrees  and  its lower  arm  extending  horizontally.  The  labrum  profile  is  almost  vertical  but broadly  rounded.  The  inner  lip  is  covered  by  the  moderately thin  callus  except for  the  moderately  thick  parietal  one     which  has  a  shallow  and  narrow  spiral depression.

 

Comparison

The  specimens  in  hand  include  apparently  different  two  forms. （The  description  is  based  on the  holotype. The  paratype  specimen  apparently  differs  from the  holotype  in  less  extra－ conical  and  somewhat  higher  spire     relatively  narrower  prome     and  somewhat more  distinct  spiral  grooves  on  the  basal  surface  of  the  body  whorl  than the holotype.  The  mentioned  difference  is  not  evidenced  to  reflect the  difference  in growth  stage  of  the  two  specimens.  They  may  represent  sexual  dimorphism. That  is  to  say  the  larger  and  broader  specimen     GK-L  6909     may  be  female  and the  slenderer  and  smaller  one GK-L  6908     male.

The  present  specimens  are  safely  included  in  Conolithus HERRMANNSEN    1847   on the  basis  of  the  diagnostic  features  mentioned  above     especially  of  the large  size     step-like  concavo-convex  spire-whorls  with  granulated  angulation     and gradually tapered  base  with  weak  spiral  grooves     although  the  former  is  slightly different  from  the  type  species  of  the  genus  in  having  remarkably  shallower  spiral furrow  at  the  parietal  lip  and  more  produced  basal  fasciole  than  the  latter. Among  the  known  species  of  Conolithus, Conolithus antidiluvianus is the closest  ally to the  present species.  The  latter  is     however     separated  from  the former  in  its  more  extraconical  spire     more  sharply  defined  shoulder     less  numerous  spiral  grooves  on  the  basal  surface     and  more  smooth  peripheral  angulation  on the  later  whorls  besides  the  difference  mentioned  above.

 

Horγzoη. Uppr  part  of  the  Dingle  Formation.

 

 

Conolithus kanayai

Pl. 22   Figs. 15-18

 

 

 

This species seems related to Conus yabey.

 

Bibliografia

 

 

·         (1) – Shuto Tsugio, (1969) “Neogene Gastropods from Panay Island, the Philippines”. Memoirs of the Faculty of Science, Kyushu Imperial University, ser. D. vol. 19 (1 ) pag. 222

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