﻿MAMMALS 
  OF 
  NORTHERN 
  COLOMBIA 
  — 
  HERSHKOVITZ 
  53 
  

  

  Measurements 
  (in 
  millimeters). 
  — 
  Head 
  and 
  body, 
  180; 
  tail, 
  200; 
  

   hind 
  foot 
  (dry, 
  with 
  claw), 
  48.0; 
  condylobasal 
  length, 
  39.1; 
  zygomatic 
  

   breadth, 
  22.2 
  ; 
  length 
  of 
  nasals, 
  17.5 
  ; 
  width 
  across 
  parietal 
  ridges, 
  13.6 
  ; 
  

   alveolar 
  length 
  of 
  molar 
  row, 
  7.1; 
  interparietal, 
  4.5X9.3 
  (48 
  percent). 
  

  

  Remarks. 
  — 
  The 
  type 
  is 
  paler 
  than 
  N. 
  s. 
  melanius 
  and 
  tarrensis^ 
  most 
  

   nearly 
  related 
  to 
  eastern 
  Colombian 
  representative 
  of 
  apicalis 
  and 
  

   widely 
  different 
  from 
  palmipes 
  of 
  the 
  island 
  of 
  Trinidad, 
  its 
  nearest 
  

   geographic 
  ally. 
  It 
  represents 
  a 
  restricted 
  race 
  and, 
  like 
  tarrensis, 
  

   appears 
  to 
  be 
  well 
  isolated 
  from 
  its 
  wide-ranging 
  neighbors, 
  melanius 
  

   and 
  apicalis. 
  

  

  This 
  water 
  rat 
  is 
  named 
  for 
  Dr. 
  G. 
  H. 
  H. 
  Tate, 
  of 
  the 
  American 
  

   Museum 
  of 
  Natural 
  History 
  and 
  one 
  of 
  the 
  co-collectors 
  of 
  the 
  type 
  

   specimen. 
  

  

  Specimens 
  examined. 
  — 
  Two. 
  The 
  type 
  and 
  a 
  juvenal 
  from 
  La 
  Latal, 
  

   both 
  in 
  the 
  collection 
  of 
  the 
  American 
  Museum 
  of 
  Natural 
  History. 
  

  

  NECTOMYS 
  (SIGMODONTOMYS) 
  ALFARI 
  RUSSULUS 
  Thomas 
  

  

  Nectomys 
  russulus 
  Thomas, 
  Ann. 
  Mag. 
  Nat. 
  Hist., 
  ser. 
  6, 
  vol. 
  20, 
  p. 
  547, 
  1897 
  

   (type 
  locality, 
  Valdivia, 
  lower 
  Cauca 
  Valley, 
  Antioquia, 
  Colombia). 
  

  

  Nectomys 
  alfari 
  riisstilus, 
  Hershkovitz, 
  Mus. 
  Zool. 
  Univ. 
  Michigan 
  Misc. 
  Publ. 
  

   No. 
  58, 
  p. 
  77, 
  1944 
  (subgenus 
  Sigmodontoviys) 
  . 
  

  

  Nectoinys 
  alfari 
  near 
  russulus, 
  Hershkovitz, 
  Mus. 
  Zool. 
  Univ. 
  Michigan 
  Misc. 
  

   Publ. 
  No. 
  58, 
  p. 
  77, 
  pi. 
  4, 
  figs. 
  1-2, 
  1944 
  (La 
  Azulita, 
  Venezuela). 
  

  

  Four 
  specimens 
  were 
  secured 
  from 
  the 
  Tarra, 
  a 
  tributary 
  of 
  the 
  

   upper 
  Rio 
  Catatumbo 
  in 
  the 
  Lake 
  Maracaibo 
  drainage 
  basin. 
  They 
  

   agree 
  with 
  the 
  individual 
  from 
  the 
  southeastern 
  edge 
  of 
  the 
  lake 
  

   previously 
  recorded 
  as 
  "near 
  russulv^.''^ 
  All 
  conform 
  with 
  the 
  type 
  of 
  

   russulus 
  in 
  the 
  more 
  important 
  cranial 
  characters 
  but 
  may 
  be 
  shown 
  

   to 
  average 
  darker 
  in 
  coloration 
  when 
  compared 
  with 
  more 
  specimens 
  

   from 
  the 
  typical 
  locality. 
  In 
  the 
  type 
  specimen, 
  the 
  present 
  series, 
  

   and 
  the 
  Venezuelan 
  specimen, 
  the 
  incisive 
  foramina 
  are 
  comparatively 
  

   widely 
  open, 
  wider 
  behind 
  than 
  in 
  front 
  with 
  the 
  posterior 
  borders 
  

   rounded 
  or 
  nearly 
  square, 
  not 
  pointed, 
  the 
  mesopterygoid 
  fossa 
  wider 
  

   than 
  length 
  of 
  first 
  upper 
  molar. 
  The 
  posterior 
  border 
  of 
  the 
  nasals 
  

   is 
  truncate 
  in 
  the 
  type, 
  obtusely 
  to 
  narrowly 
  pointed 
  in 
  the 
  others. 
  

   Comparisons 
  with 
  the 
  original 
  series 
  of 
  Nectomys 
  alfari 
  efficax 
  Gold- 
  

   man, 
  from 
  eastern 
  Panama, 
  confirm 
  its 
  subspecific 
  distinction 
  from 
  

   russulus. 
  

  

  Measurements 
  of 
  the 
  type 
  specimen 
  of 
  russulus.^ 
  taken 
  in 
  the 
  British 
  

   Museum, 
  are 
  as 
  follows 
  : 
  Condylobasal 
  length, 
  33.5 
  ; 
  zygomatic 
  breadth, 
  

   19.3 
  ; 
  length 
  of 
  nasals, 
  13.9 
  ; 
  width 
  across 
  parietal 
  ridges, 
  12.7 
  ; 
  alveola-r 
  

   length 
  of 
  molar 
  row, 
  5.9; 
  interparietal, 
  3.5X8.6 
  mm. 
  The 
  type 
  is 
  

   slightly 
  tawnier 
  in 
  coloration 
  than 
  the 
  type 
  of 
  esmeraldarum. 
  

  

  