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Number  488 
19  April  2002 


Contributions 
IN  Science 


Larval  Blennies  erom  the  Galapagos  and 
Cocos  Islands:  Families  Tripterygiidae, 
Dactyloscopidae,  and  Chaenopsidae 
(Perciformes,  Blennioidei) 

Guillermo  A.  Herrera  and 
Robert  J.  Lavenberg 


OF  Los  Angeles  County 


Natural  History  Museum 


Serial 

Publications 

OL  THE 

Natural  History 
Museum  ol 
Los  Angeles 
County 


Scientific 

Publications 

Committee 

John  Heyning,  Deputy  Director 
for  Research  and  Collections 
John  M.  Harris,  Committee  Chairman 
Brian  V.  Brown 
Kenneth  E.  Campbell 
Kirk  Fitzhugh 
Karen  Wise 

K.  Victoria  Brown,  Managing  Editor 


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Printed  at  Allen  Press,  Inc.,  Lawrence,  Kansas 
ISSN  0459-8113 


Larval  Blennies  erom  the  Galapagos  and 
Cocos  Islands:  Families  Tripterygiidae, 
Dactyloscopidae,  and  Chaenopsidae 
(Percieormes,  Blennioidei) 


Guillermo  A.  Herrera^  and 
Robert  J.  Lavenberg^ 


ABSTRACT.  Postflexion  larvae  of  ten  eastern  Pacific  blennioid  species  from  the  Galapagos  Islands  and 
Cocos  Island  are  described.  Three  families  are  treated:  Tripterygiidae,  Dactyloscopidae,  and  Chaenopsidae. 
The  identifications  were  based  on  meristic  data,  and  on  comparisons  of  morphology  between  adults  and 
large  larvae.  The  larvae  from  the  Galapagos  Islands  are  Lepidonectes  corallicoia  (Tripterygiidae);  Dacty- 
loscopus  lacteus,  Myxodagnus  sagitta,  Platygillellus  rubellulus,  and  GHlellus  semicinctus  (Dactyloscopidae); 
and  Acanthemblemaria  castroi  and  Chaenopsis  schmitti  (Chaenopsidae).  The  larvae  from  Cocos  Island  are 
Dactyloscopus  pectoralis  fallax  (Dactyloscopidae);  and  Acanthemblemaria  atrata  and  Stathmonotus  sp. 
(Chaenopsidae). 

All  larvae  described  herein  possess  the  following  characters:  a relatively  long  and  slender  body;  a me- 
lanophore  anterior  to  the  tip  of  the  cleithral  symphysis;  ventral  midline  melanophores  between  pterygio- 
phores  of  the  anal  fin;  and  a small  head  with  a short  and  generally  rounded  snout  (except  in  dactyloscopids 
and  in  the  chaenopsid  Chaenopsis  schmitti).  Larvae  of  Lepidonectes  corallicoia  (Tripterygiidae)  have  a 
specific  arrangement  of  melanophores  on  the  pterygiophores  of  the  third  dorsal  fin  and  at  the  base  of  spines 
of  the  second  dorsal  fin;  pigment  is  found  ventrally  on  the  caudal  peduncle  and  on  the  posterior  margin 
of  the  hypural  plates.  Larvae  of  the  dactyloscopids  {Dactyloscopus  lacteus,  Myxodagnus  sagitta,  Platygil- 
lellus rubellulus,  and  Gillellus  semicinctus)  have  large  and  pointed  heads,  short  preanal  length  (30-35% 
standard  length  (SL)),  and  prominent  dorsal  and  anal  fins.  The  dactyloscopid  larvae  can  be  identified  by 
specific  combinations  of  characters:  presence,  number,  and  size  of  head  melanophores;  presence  of  pig- 
mentation along  dorsal  margin  of  the  body;  presence  of  melanophores  on  the  hypural  borders;  and  fin 
structure  and  meristics.  Most  chaenopsid  larvae  possess  a large  and  elongate  melanophore  in  the  midline 
along  the  basipterygium,  a melanophore  on  the  jaw  angle,  pigment  dorsally  to  the  anus,  and  a long  preanal 
length  (40-50%  SL).  Characters  described  herein  suggest  that  some  larval  attributes  may  be  informative 
for  the  elucidation  of  phylogenetic  relationships  within  each  family. 

RESUMEN.  Se  describen  las  larvas  en  estado  de  postflexion  de  diez  blenioideos  del  pacifico  este  de  las 
Islas  Galapagos  y de  Isla  del  Coco.  Las  familias  consideradas  son  Tripterygiidae,  Dactyloscopidae  y Chaen- 
opsidae. Las  identificaciones  se  basaron  en  informacion  meristica  y en  comparaciones  de  morfologia  de 
adultos  con  larvas  avanzadas.  Las  larvas  de  las  islas  Galapagos  son  Lepidonectes  corallicoia  (Tripterygi- 
idae); Dactyloscopus  lacteus,  Myxodagnus  sagitta,  Platygillellus  rubellulus  y Gillellus  semicinctus  (Dacty- 
loscopidae); y Acanthemblemaria  castroi  y Chaenopsis  schmitti  (Chaenopsidae).  Las  larvas  de  Isla  del  Coco 
son  Dactyloscopus  pectoralis  fallax  (Dactyloscopidae),  y Acanthemblemaria  atrata  y Stathmonotus  sp. 
(Chaenopsidae). 

Caracteristicas  presentes  en  las  larvas  de  todas  las  especies  son:  cuerpo  relativamente  largo  y elongado, 
un  melanoforo  anterior  de  la  sinfisis  de  los  cleitros,  una  hilera  ventral  de  melanoforos  entre  los  pterigioforos 
de  la  aleta  anal,  y una  cabeza  pequeha  con  un  hocico  corto  y redondeado  (excepto  en  los  dactiloscopidos 
y el  chaenopsido  Chaenopsis  schmitti).  Las  larvas  del  blenido  de  tres  aletas,  Lepidonectes  corallicoia,  tienen 
una  configuracion  espedfica  de  melanoforos  en  los  pterigioforos  de  la  tercera  aleta  dorsal  y en  la  base  de 
algunas  espinas  de  la  segunda  aleta  dorsal;  tienen  ademas  pigmento  ventral  en  el  pedunculo  caudal  y en 
el  margen  posterior  de  las  placas  hipurales.  Los  dactiloscopidos  {Dactyloscopus  lacteus,  Myxodagnus  sag- 
itta, Platygillellus  rubellulus  y Gillellus  semicinctus)  tienen  larvas  con  una  cabeza  grande  y puntiaguda, 
una  distancia  preanal  corta  (30-35%  longitud  estandar  (LE))  y aletas  dorsal  y anal  prominentes.  Las 
especies  pueden  identificarse  mediante  combinaciones  especificas  de  caracteres  tales  como  presencia,  nu- 
mero  y tamano  de  melanoforos  cefalicos;  presencia  de  pigmento  dorsal  sobre  el  cuerpo  y en  el  borde 
posterior  de  las  placas  hipurales;  y caracteres  meristicos  de  las  aletas.  Las  mayoria  de  las  larvas  de  los 
chaenopsidos  poseen  un  melanoforo  grande  y elongado  ventral  al  basipterigio,  un  melanoforo  en  el  angulo 
mandibular,  pigmento  dorsal  sobre  el  ano,  y una  mayor  distancia  preanal  (40-50%  LE).  Los  caracteres 
larvales  descritos  en  este  trabajo  sugieren  que  algunos  atributos  pueden  ser  informativos  para  la  elucidacion 
de  relaciones  filogeneticas  dentro  de  cada  familia. 


Contributions  in  Science,  Number  488,  pp.  1-15 
Natural  History  Museum  of  Los  Angeles  County,  2002 


INTRODUCTION 

The  blennioids  are  oviparous  fishes  (except  for 
three  viviparous  genera)  that  lay  their  eggs  attached 
to  a nest  substrate,  and  exhibit  male  parental  care. 
The  larvae  are  elongate  and  hatch  with  pigmented 
eyes  and  sparse  pigmentation  (Matarese  et  ah, 
1984;  Stepien,  1986;  Watson,  1996).  Common  fea- 
tures are  the  presence  of  large  melanophores  dor- 
sally  on  the  swimbladder  and  gut  and  small  mela- 
nophores along  the  ventral  margin  of  the  trunk,  be- 
tween the  pterygiophores  of  the  long  anal  fin  (Wat- 
son, 1996;  Cavalluzzi,  1997). 

The  sizes  of  larvae  at  hatching  and  flexion  vary 
depending  on  the  species  (Matarese  et  ah,  1984), 
and  the  larvae  do  not  show  striking  pigment  pat- 
terns or  morphological  adaptations  for  pelagic  life. 
Aside  from  some  Blenniidae,  the  larvae  of  most 
blennioid  families  are  largely  limited  to  coastal  wa- 
ters (Watson,  1996).  Indeed,  some  larvae  have  been 
observed  to  remain  actively  in  coastal  areas  as  they 
school  in  groups  around  kelp  and  other  algae  (Ste- 
pien et  ah,  1997). 

Few  characters  are  shared  by  all  blennoid  larvae, 
and  most  of  them  have  been  summarized  by  Ma- 
tarese et  al.  (1984),  Watson  (1996),  and  Cavalluzzi 
(1997).  These  are:  body  moderately  elongate;  pre- 
anal  distance  between  30  and  50%  of  the  standard 
length  (SL);  large  swimbladder;  melanophores  on 
the  ventral  margin  of  the  trunk  (between  pterygio- 
phores of  the  anal  fin);  a melanophore  on  the  tip 
of  the  cleithral  symphysis  (Herrera  and  Lavenberg, 
1999);  and  six  branchiostegal  rays. 

Matarese  et  al.  (1984)  summarized  the  larval 
characters  of  some  Blennioidei,  at  a time  when  not 
many  descriptions  were  available.  The  best  known 
larvae  are  those  of  the  families  Blenniidae  and  Trip- 
terygiidae,  probably  because  of  their  wider  distri- 
butions and  greater  species  numbers.  The  knowl- 
edge of  the  larvae  of  the  other  four  families,  which 
are  predominantly  from  the  New  World,  has  in- 
creased in  recent  years  with  the  descriptions  of  lar- 
vae from  the  Gulf  of  California  (Brogan,  1992),  the 
California  Current  region  (Watson,  1996),  and  the 
western  Atlantic  (Cavalluzzi,  1997).  The  larvae  of 
species  from  the  southeastern  Pacific  are  less  well 
known  (Balbontin  and  Perez,  1979;  Perez,  1979). 

Nineteen  Blennioidei  are  known  from  the  Gala- 
pagos Islands,  twelve  of  which  are  endemic  (Grove 
and  Lavenberg,  1998).  They  belong  to  the  families 
Tripterygiidae  (one  species),  Dactyloscopidae  (five 
species),  Blenniidae  (three  species),  Labrisomidae 
(seven  species),  and  Chaenopsidae  (three  species). 
No  species  of  the  family  Clinidae  are  known  from 
the  archipelago.  In  this  paper,  field-collected  speci- 
mens mainly  from  the  Galapagos  Islands,  obtained 
from  plankton  samples  collected  during  the  Allan 
Hancock  expeditions,  are  described.  Additionally, 


1-2.  Natural  History  Museum  of  Los  Angeles  County, 
Research  and  Collections,  900  Exposition  Boulevard,  Los 
Angeles,  California  90007. 

2 ■ Contributions  in  Science,  Number  488 


the  larvae  of  three  species  from  Cocos  Island,  Costa 
Rica,  are  included.  The  material  considers  postflex- 
ion larval  stages  and  some  juveniles.  Larvae  of  the 
following  species  are  described:  Tripterygiidae, 
Lepidonectes  corallicola  (Kendall  and  Radcliffe, 
1912);  Dactyloscopidae,  Dactyloscopus  lacteus 
(Myers  and  Wade,  1946),  D.  pectoralis  fallax 
(Dawson,  1975),  Myxodagnus  sagitta  (Myers  and 
Wade,  1946),  Platygillellus  rubellulus  (Kendall  and 
Radcliffe,  1912),  and  Gillellus  semicinctus  (Gilbert, 
1890);  and  Chaenopsidae,  Acanthemblemaria  cas- 
troi  (Stephens  et  al.,  1966),  A.  atrata  (Hastings  and 
Robertson,  1999),  Chaenopsis  schmitti  (Bohlke, 
1957),  and  Stathmonotus  sp.  The  larvae  of  D.  pec- 
toralis fallax,  A.  atrata,  and  Stathmonotus  sp.  were 
collected  in  Cocos  Island.  Larvae  of  six  species  of 
the  family  Labrisomidae  (from  the  seven  species  cit- 
ed for  the  archipelago)  were  described  separately 
(Herrera  and  Lavenberg,  1999). 

MATERIALS  AND  METHODS 

Most  of  the  plankton  samples  were  collected  by  the  RW 
Velero  III,  during  the  Allan  Hancock  Pacific  expedition 
cruises  to  the  eastern  Pacific  and  Galapagos  Islands.  Sam- 
pling sites  included  Espanola,  Santa  Maria,  Santa  Cruz, 
Isabela,  Baltra,  and  Genovesa  Islands  (Eraser,  1943).  A 
single  sample  was  collected  in  Chatham  Bay,  Cocos  Island, 
Costa  Rica.  Samples  were  normally  collected  at  night  (at 
anchorage),  using  an  electric  light  and  dip  nets.  The  larvae 
are  housed  in  the  larval  fish  collection  at  the  Natural  His- 
tory Museum  of  Los  Angeles  County  (LACM).  The  spec- 
imens were  measured  to  the  nearest  0.1  mm  and  illustrat- 
ed with  a camera  lucida.  The  size  range  of  the  series  il- 
lustrated was  determined  by  the  available  material.  Al- 
though the  larval  series  are  not  complete  because  of  the 
sporadic  nature  of  the  sampling,  they  still  contain  valuable 
ontogenetic  information.  Meristic  data  were  obtained 
from  collection  specimens  and  from  the  literature.  Mea- 
surements and  definitions  follow  those  of  Leis  and  Rermis 
(1983). 

The  larvae  of  the  three  species  of  Blenniidae  from  Gal- 
apagos, Hypsoblennius  brevipinnis  (Gunther,  1861), 
Ophioblennius  steindachneri  (Jordan  and  Evermann, 
1898),  and  Plagiotremmus  azalea  (Jordan  and  Bollman, 
1890),  were  also  found  together  with  the  larvae  described 
here  and  in  a previous  work  (Herrera  and  Lavenberg, 
1999).  These  three  species  have  a wide  distributional 
range  in  the  eastern  Pacific  and  their  larvae  have  been 
described  from  the  California  region  (Watson,  1996).  Lar- 
vae of  another  blennioid,  the  dactyloscopid  Dactylagnus 
mundus  (Gill,  1862),  were  not  found  in  the  samples. 

RESULTS 

The  following  descriptions  include  general  charac- 
terizations of  morphology,  dorsal-  and  anal-fin  de- 
velopment, and  pigmentation.  The  larval  series  are 
limited  by  the  available  material  collected.  For 
those  species  represented  by  a few  individuals  the 
descriptions  are  restricted  to  a usually  narrow  size 
range.  Meristic  data  and  information  about  preanal 
distance,  a helpful  diagnostic  character  of  larval 
blennioid  families,  are  summarized  in  Table  1. 

Herrera  and  Lavenberg:  Larval  blennies  from  Galapagos 


Table  1.  Selected  meristic  and  morphologic  data  for  species  of  Tripterygiidae,  Dactyloscopidae,  Blenniidae,  and  Chaenopsidae  included  in  this  study. 

Pigmentation 

Dorsal  Dorsal  Hyp.  Ventral  Preanal 

Species  Vertebrae  DorsaP"  AnaP'  PT'"  head  trunk  border  gut  distance  (%)  Reference 


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Contributions  in  Science,  Number  488 


Herrera  and  Lavenberg:  Larval  blennies  from  Galapagos  I 3 


t Not  found  in  samples  but  present  in  the  Galapagos. 

# Collected  from  Cocos  Island. 

References:  (1)  Bussing  (1991);  (2)  Dawson  (1976);  (3)  Brogan  (1992);  (4)  Dawson  (1975);  (5)  Dawson  (1974);  (6)  Dawson  (1977);  (7)  Watson  (1996);  (8)  Rosenblatt  and  McCosker 
(1988);  (9)  Stephens  (1963);  (10)  Stephens  et  al.  (1966);  (11)  Hastings  and  Springer  (1994). 


DESCRIPTION  OF  LARVAE 
Family  Tripterygiidae 

A single  triperygiid  occurs  in  the  Galapagos  Islands, 
the  endemic  Lepidonectes  corallicola.  In  general, 
the  larvae  of  the  Tripterygiidae  are  elongate  and 
slightly  compressed;  have  small  short  and  rounded 
heads  with  no  spination;  have  dorsal,  anal,  and 
pectoral  fins  that  develop  early  (shortly  after  flex- 
ion); and  have  the  spines  of  the  first  dorsal  and  on 
the  anal  fins  that  form  last  (Leis  and  Rennis,  1983). 

Lepidonectes  corallicola 
(Kendall  and  Radcliffe,  1912) 

Figure  1 

MATERIAL  EXAMINED.  From  2,281  speci- 
mens (6.2-18.3  mm  SL),  five  are  illustrated;  LACM 
45614-6  (8.3,  10.0,  13.0,  and  15.1  mm  SL)  and 
LACM  45621-17  (17.2  mm  SL). 

MORPFIOLOGY.  The  body  is  moderately  elon- 
gate (preanal  length  41-”43%  body  length  (BL)) 
with  a small  head  and  rather  small  and  rounded 
snout.  Flexion  completed  by  8.0  mm.  Anal  fin, 
third  dorsal  fin,  and  pelvic  fins  are  apparent  by  8.0 
mm.  First  and  second  dorsal  fin  apparent  by  13.0 
mm  SL.  Pores  of  the  preopercular  and  circumor- 
bital  sensory  canal  systems  are  evident  by  17.2 
mm  SL. 

PIGMENTATION.  In  small  larvae  (6.2  mm)  a 
single  dorsal  melanophore  is  present  on  the  nape; 
this  melanophore  becomes  embedded  with  growth. 
Other  cephalic  pigmentation  includes  a pair  of  me- 
lanophores  on  the  hindbrain  (Figs,  la-b),  which  in- 
creases to  three  pairs  with  the  appearance  of  pairs 
on  the  midbrain  and  forebrain  (Fig.  le).  Gut  pig- 
ment consists  of  a single  melanophore  located  ven- 
troanteriorly  (behind  insertion  of  the  pelvic  fins). 

By  8.3  mm  SL  three  to  five  melanophores  are 
present  on  the  ventral  midline  of  the  caudal  pedun- 
cle, and  the  posterior  margins  of  the  upper  and 
lower  hypural  plates  each  possess  a single  mela- 
nophore. By  10.0  mm,  dorsal  midline  melano- 
phores are  associated  with  the  posterior  portion  of 
the  third  dorsal  fin,  and  the  posterior  margin  of  the 
upper  and  lower  hypural  plates  each  possess  two 
melanophores.  By  15.1  mm  SL,  the  second  dorsal 
fin  has  a single  melanophore  at  the  base  of  spines 
1,  3,  and  7-11  (rarely  associated  with  spines  2 and 
6),  the  third  dorsal  fin  has  a single  melanophore  at 
the  base  of  each  soft  ray,  the  posterior  margins  of 
the  dorsal  and  ventral  hypural  plates  have  a wide 
band  of  pigment,  two  melanophores  are  present  on 
the  upper  jaw,  and  small  melanophores  pepper  the 
membrane  between  rays  of  the  caudal  fin,  mainly 
in  the  lower  half.  By  17.2  mm  SL,  the  juvenile  stage 


is  observed.  Additional  pigment  includes  a lateral 
band  of  small  melanophores  extending  from  the 
pectoral-fin  base  to  the  end  of  the  caudal  peduncle. 

REMARKS.  Below  10.0  mm  SL,  the  larvae  are 
similar  in  appearance  to  some  labrisomids,  espe- 
cially those  species  lacking  preopercular  spines. 
However,  pigmentation,  meristics,  and  morpho- 
metries can  differentiate  them.  In  L.  corallicola  dor- 
sal midline  melanophores  develop  from  posterior  to 
anterior  (opposite  for  Malacoctenus  zonogaster,  La- 
brisomidae),  length  to  the  origin  of  the  third  dorsal 
fin  is  60-63%  SL  in  L.  corallicola  (68-71%  SL  in 
M.  zonogaster),  and  preanal  distance  is  41-43%  SL 
in  L.  corallicola  (38-41%  in  M.  zonogaster).  After 
10.0  mm  SL,  the  presence  of  three  distinct  dorsal 
fins  in  L.  corallicola  separates  this  species  from  the 
labrisomids. 

Family  Dactyloscopidae 

The  family  Dactyloscopidae  is  restricted  to  the  New 
World,  in  the  Pacific  and  Atlantic  Oceans.  A few 
descriptions  of  dactyloscopid  larvae  from  the  Gulf 
of  Galifornia  (Brogan,  1992),  Baja  California  (Wat- 
son, 1996),  and  the  Atlantic  (Cavalluzzi  1997)  are 
available.  From  these,  the  larvae  of  the  sand  star- 
gazers can  be  characterized  as  having  an  elongate 
body,  a short  and  compact  gut,  long  and  relatively 
high  dorsal  and  anal  fins,  jugular  pelvic  fins,  5 + 5 
principal  caudal  rays,  and  a large  head  with  point- 
ed snout  and  no  cirri.  The  preanal  length  is  short, 
compared  to  that  of  other  families,  and  ranges  from 
28-35%  SL  (see  Table  1).  The  species  from  the  Gal- 
apagos show  specific  arrangements  of  cephalic,  hy- 
pural, and  trunk  pigment.  The  posterodorsal  region 
of  the  swimbladder  is  pigmented,  but  it  is  difficult 
to  see  the  melanophores,  especially  in  larger  or 
more  robust  larvae  (such  as  Dactyloscopus). 

Dactyloscopus  lacteus 
(Myers  and  Wade,  1946) 

Figure  2 

MATERIAL  EXAMINED.  Only  two  specimens 
collected;  LACM  45628-5  (7.7  mm  SL)  and  LACM 
45617-2  (9.2  mm  SL). 

MORPHOLOGY.  The  head  is  large  and  deep 
with  a pointed  snout  and  a slight  projection  of  the 
tip  of  the  lower  jaw.  Preanal  length  reaches  31- 
34%  SL.  The  larvae  lack  a notch  on  the  ventral 
margin  of  the  caudal  peduncle,  a character  that  is 
present  in  adults  of  many  Dactyloscopus  species 
(Dawson,  1975).  At  7.7  mm,  the  anal-fin  rays  are 
longer  and  more  prominent  than  the  dorsal-fin 
rays,  indicating  that  the  anal  fin  develops  earlier.  At 
this  size,  only  the  rayed  portion  of  the  dorsal  fin 


Figure  1 Larvae  of  Lepidonectes  corallicola:  (a)  8.3  mm  (b)  10.0  mm  (c)  13.0  mm  (d)  15.1  mm  (LACM  45614-6) 
(e)  17.2  mm  (LACM  45621-17) 


4 ■ Contributions  in  Science,  Number  488 


Herrera  and  Lavenberg:  Larval  blennies  from  Galapagos 


Contributions  in  Science,  Number  488 


Herrera  and  Lavenberg:  Larval  blennies  from  Galapagos  ■ 5 


has  developed  (Fig.  2a).  By  9.2  mm  all  dorsal-fin 
spines  have  formed  although  they  are  not  yet  at 
their  maximum  length  and  sensory  pores  have 
formed  on  the  preopercular  border,  the  ventral 
margin  of  the  lower  jaw  and  below  the  eye  (Fig. 
2b). 

PIGMENTATION.  In  addition  to  the  pigmenta- 
tion anterior  to  the  tip  of  the  basipterygium,  Dac- 
tyloscopus  lacteus  has  another  small  melanophore 
on  the  basipterygium,  close  to  the  tip.  The  two  me- 
lanophores  are  very  close  and  usually  difficult  to  dis- 
tinguish from  each  other  when  expanded.  Two  large 
dendritic  melanophores  are  present;  one  dorsally  on 
the  head,  and  the  other  ventrally  on  the  gut.  No 
melanophores  occur  dorsally  along  the  trunk  or  on 
the  caudal  peduncle.  The  posterior  margins  of  the 
hypural  plates  are  pigmented.  This  differs  from  D. 
pectoralis  (Brogan,  1992),  D.  byersi  (Watson,  1996), 
and  D.  pectoralis  fallax  (Dawson,  1975). 


Dactyloscopus  pectoralis  fallax 
(Dawson,  1975) 

Figure  3 

MATERIAL  EXAMINED.  Description  of  a sin- 
gle specimen,  LACM  45658  (10.0  mm  SL),  from 
three  larvae  (all  near  10.0  mm  SL)  collected  in  Co- 
cos Island,  Costa  Rica. 

MORPHOLOGY.  The  body  shape  is  similar  to 
that  of  Dactyloscopus  lacteus.  The  preanal  length 
is  30-32%  BL.  At  10.0  mm  SL  head  pores  or  dorsal 
spines  have  not  yet  formed,  which  may  differ  from 
D.  lacteus,  because  the  latter  species  had  them  by 
9.2  mm  (see  Fig.  2b).  The  soft  dorsal  has  formed 
although  it  has  not  reached  its  maximum  size,  and 
the  dorsal  spines  are  small  projections. 

PIGMENTATION.  Dactyloscopus  pectoralis  fal- 
lax has  a single  dendritic  melanophore  dorsally  on 
the  head  and  another  ventrally  on  the  gut.  The  sole 
difference  between  D.  pectoralis  and  D.  pectoralis 


Figure  3 Larva  of  Dactyloscopus  pectoralis  fallax:  10.0  mm  (LACM  45658-2) 


6 ■ Contributions  in  Science,  Number  488 


Herrera  and  Lavenberg:  Larval  blennies  from  Galapagos 


Figure  4 Larvae  of  Myxodagnus  sagitta:  (a)  7.3  mm  (b)  8.8  mm  (LACM  45625-7)  (c)  11.6  mm  (LACM  45623-10) 
(d)  13.4  mm  (LACM  45625-7) 


fallax  is  the  presence  in  the  former  of  several  me- 
lanophores  ventrally  on  the  gut  (Brogan,  1992)  that 
are  not  present  in  the  latter.  However,  more  speci- 
mens of  D.  pectoralis  fallax  should  be  examined  to 
determine  whether  this  pigment  appears  later  in  the 
ontogeny. 

Myxodagnus  sagitta 
(Myers  and  Wade,  1946) 

Figure  4 

MATERIAL  EXAMINED.  From  a total  eighty- 
two  specimens  collected,  in  the  size  range  of  7.0- 
14.0  mm,  four  are  used  for  description;  LACM 
45625-7  (7.3  and  8.8  mm  SL),  LACM  45623-10 
(11.6  mm  SL),  and  LACM  45625-7  (13.4  mm  SL). 

MORPHOLOGY.  Among  the  larval  dactylos- 
copids  studied,  this  species  has  the  most  slender  and 
elongate  body,  the  smallest  head,  and  the  shortest 


preanal  distance  (28-30%  BL).  The  anal-  and  dor- 
sal-fin rays  have  developed  by  7.0  mm  (Fig.  4a), 
whereas  the  dorsal  spines  develop  later  (Fig.  4c) 
The  head  is  deep  in  small  larvae,  as  in  most  dac- 
tyloscopids,  but  becomes  depressed  with  develop- 
ment. The  anterior  projection  of  the  lower  jaw  is 
slight  in  small  larvae,  and  increases  with  size.  Pelvic 
fins  develop  at  an  early  stage  (Fig,  4a),  but  they 
remain  smaller  than  in  all  other  species  of  the  fam- 
ily. 

PIGMENTATION.  The  cephalic  pigmentation 
pattern  of  Myxodagnus  sagitta  resembles  that  of 
Dactyloscopus  lacteus,  with  a large  dendritic  me- 
lanophore  above  the  head  and  below  the  gut.  Fur- 
thermore, a melanophore  is  present  at  the  base  of 
each  dorsal  ray,  except  in  the  last  one  to  two  rays. 
A small  melanophore  develops  on  the  ventral  mar- 
gin of  the  caudal  peduncle;  these  melanophores  are 
lacking  in  M.  opercularis  (Brogan,  1992;  Watson, 


Contributions  in  Science,  Number  488 


Herrera  and  Lavenberg:  Larval  blennies  from  Galapagos  ■ 7 


a 


Figure  5 Larvae  of  Platygillellus  rubellulus:  (a)  8.9  mm  (LACM  45614-11)  (b)  11.1  mm  (LACM  45621-10) 


1996).  In  smaller  larvae,  the  posterior  edge  of  each 
hypural  plate  has  one  small  melanophore  on  the 
border;  these  melanophores  increase  with  develop- 
ment forming  bands  of  pigment.  In  some  specimens 
a small  melanophore  develops  directly  anterior  to 
the  anus  (Fig.  4d). 

Platygillellus  rubellulus 
(Kendall  and  Radcliffe,  1912) 

Figure  5 

MATERIAL  EXAMINED.  Two  specimens,  out 
of  fifteen  collected  (size  range  8.0-11.1  mm  SL)  are 
described;  LACM  45614-11  (8.9  mm  SL)  and 
LACM  45621-10  (11.1  mm  SL). 

MORPHOLOGY.  The  body  shapes  of  Platygil- 
lellus rubellulus  and  Dactyloscopus  lacteus  larvae 
are  similar  in  having  large  heads  and  deep  bodies 
anteriorly,  but  differing  in  cephalic  pigmentation. 
The  preanal  length  reaches  33-35%  BL,  which  is 
the  longest  among  the  studied  dactyloscopids.  At 
11.1  mm,  three  pores  occur  above  the  eye  and  one 
occurs  on  the  margin  of  the  lower  jaw.  The  dorsal 
fin  is  notched  anteriorly,  with  the  third  spine  short- 
er than  the  adjacent  ones,  anterior  and  posterior.  In 
addition,  the  third  and  fourth  spines  are  more  sep- 
arated from  one  another  than  other  dorsal  spines. 
The  last  four  dorsal  spines  decrease  in  size  and  first 
four  dorsal-fin  rays  increase  progressively  in  size. 
The  relative  sizes  of  spines  and  rays  resembles  a 
doubly  notched  dorsal  fin  (Fig.  5b). 

PIGMENTATION.  Pigment  pattern  is  the  same  in 
both  illustrated  larvae.  Two  pairs  of  melanophores 

8 ■ Contributions  in  Science,  Number  488 


occur  dorsally  on  the  head;  a large  pair  above  the 
midbrain,  and  a small  pair  over  the  forebrain.  A sin- 
gle melanophore  is  present  on  the  nape.  Except  for 
a small  single  melanophore  before  the  anus,  no  ven- 
tral melanophores  are  found  on  the  gut,  A single  and 
small  melanophore  occurs  on  the  ventral  margin  of 
the  caudal  peduncle  just  behind  the  last  anal-fin  ray. 
Another  ventral  midline  melanophore  is  found  im- 
mediately anterior  to  the  ventral  hypural  plate.  This 
melanophore  varies  in  position  from  the  space  be- 
tween fourth  and  fifth  caudal  rays  (lower  hypural), 
on  the  fifth  ray,  in  the  space  between  the  last  two 
procurrent  caudal  rays,  and  slightly  in  front  of  the 
first  procurrent  caudal  ray. 

Gillellus  semicinctus  (Gilbert,  1890) 

Figure  6 

MATERIAL  EXAMINED.  Of  the  forty  speci- 
mens collected,  three  are  used  for  description: 
LACM  45614-19  (6.5,  10.0,  and  12.4  mm  SL). 

MORPHOLOGY.  The  larvae  are  more  elongate 
than  those  of  Dactyloscopus  lacteus  and  the  head 
is  proportionally  smaller.  The  preanal  length  reach- 
es 30-32%  SL.  Figure  6 shows  the  approximate 
formational  sequence  of  the  dorsal-  and  anal-fin 
spines  and  rays,  and  the  subtle  projection  of  the 
lower  jaw  with  development.  At  6.5  mm  flexion  is 
complete,  the  anal  fin  is  beginning  to  develop,  and 
the  dorsal  fin  has  not  formed  (Fig.  6a).  In  the  larg- 
est larva,  12.4  mm,  the  first  three  dorsal  spines, 
which  are  separated  from  the  following  spines  in 
the  form  of  a finlet,  are  present.  Their  lengths  de- 

Herrera  and  Lavenberg:  Larval  blennies  from  Galapagos 


Figure  6 Larvae  of  Gillellus  semicinctus-.  (a)  6.5  mm,  (b)  10.0  mm,  and  (c)  12.4  mm  (LACM  45614-19) 


crease  progressively  from  the  first  to  the  third  (Fig. 
6c).  Posteriorly,  the  dorsal  spines  and  rays  are  ap- 
proximately the  same  size,  and  the  border  of  the 
dorsal  fin  is  straight. 

PIGMENTATION.  Pigment  pattern  does  not 
change  in  the  size  range  studied.  The  larvae  of  Gil- 
lellus semicinctus  have  two  or  three  small  melano- 
phores  ventral  to  the  gut.  One  (or  two  in  some  lar- 
vae) is  always  just  posterior  to  the  insertion  of  the 
pelvic-fin  rays,  and  the  second  is  located  more  pos- 
teriorly next  to  the  anus.  A ventral  and  internal 
melanophore  is  also  present  behind  the  cleithra. 
Pigment  is  absent  dorsally  on  the  head,  which  is  an 
uncommon  feature  in  the  family  that  has  been  also 
reported  in  larvae  of  two  other  species  of  Gillellus 
from  the  western  Atlantic,  G.  jacksoni  and  G.  ur- 
anidea  (Cavalluzzi,  1997).  This  lack  of  pigment 
may  be  a reductive  specialization  characterizing  the 
genus. 

Watson  (1996)  described  larvae  of  a Gillellus 
species,  tentatively  ascribed  to  semicinctus.  Fiow- 
ever,  in  his  series  the  pretransformation  specimens 
(<13.3  mm)  develop  preopercular  spines  and  a 
ventral  series  of  melanophores  at  the  anal-fin  base 
that  is  not  continuous.  The  larvae  described  here 
do  not  have  preopercular  spines  and  a continuous 


melanophore  series  occurs  between  pterygiophores. 
The  differences  may  be  due  to  intraspecific  varia- 
tion or  the  larvae  may  belong  to  different  species. 

REMARKS  ON  DACTYLOSCOPID  LARVAE 

The  relationships  between  the  eight  dactyloscopid 
genera  have  been  studied  by  Doyle  (1998)  using 
morphological  data.  Heteristius  is  the  basalmost 
taxon,  and  Platygillellus  is  the  next  basalmost  tax- 
on. The  remaining  six  genera  are  divided  into  two 
clades;  one  of  them  includes  Gillellus  (together  with 
Leurochilus  and  Sindoscopus)  and  the  other  com- 
prises Dactyloscopus,  Dactylagnus,  and  Myxodag- 
nus.  Some  of  the  larval  characters  presented  here 
are  congruent  with  the  relationships  hypothesized 
by  Doyle  (1998).  A large,  single,  medial  dendritic 
melanophore  occurs  dorsally  on  the  head  and  ven- 
tral to  the  gut  in  the  derived  clade  comprising  Dac- 
tylagnus, Myxodagnus,  and  Dactyloscopus.  These 
genera  also  share  the  same  general  body  shape, 
with  a straight  anterior  profile  of  the  dorsal  fin  and 
a shorter  preanal  distance.  In  the  other  derived 
clade,  the  larvae  of  Gillellus  lack  cephalic  melano- 
phores, which  represents  a derived  condition.  Un- 
fortunately, larvae  of  the  other  two  genera  of  the 


Contributions  in  Science,  Number  488 


Herrera  and  Lavenberg:  Larval  blennies  from  Galapagos  ■ 9 


clade,  Leurochilus  and  Sindoscopus,  are  not 
known. 

The  larvae  of  the  phylogenetically  more  primitive 
Platygillellus  show  features  that  can  be  considered 
plesiomorphic  and  include  small  melanophores  in 
pairs  above  the  brain  (vs.  large  and  single),  a longer 
preanal  distance  (vs.  shorter),  a dorsal  fin  divided 
into  regions  (vs.  straight  margin),  and  several  small 
ventral  melanophores  on  the  gut  (vs.  single  and 
large). 

Family  Chaenopsidae 

The  tube  blennies  are  found  in  tropical  and  tem- 
perate coastal  waters  of  the  New  World,  in  both 
the  eastern  Pacific  and  western  Atlantic.  Compared 
to  other  blennies,  chaenopsid  larvae  have  a rela- 
tively longer  and  straighter  gut  with  a prominent 
dorsally  pigmented  swimbladder.  Most  species  have 
a large  and  elongate  melanophore  midventral  at  the 
basipterygium  area.  Other  larval  characters  include 
the  presence  of  pigment  dorsally  to  the  anus,  pelvic 
fins  that  are  inserted  close  to  the  base  of  the  pec- 
toral fin,  rugae  in  the  gut,  ventral  pigment  on  gut 
and  breast,  no  dorsal  pigmentation,  and  a broad 
and  serrated  premaxilla  with  a long  ascending  pro- 
cess (Brogan,  1992). 

Acanthemblemaria  castroi 
(Stephens  et  ah,  1966) 

Figure  7 

MATERIAL  EXAMINED.  From  the  712  larvae 
examined,  in  the  size  range  of  5.3  mm  notochord 
length  (NL)  to  16  mm  SL,  five  were  used  for  de- 
scriptions: LACM  45621-1  (5.3  mm  NL),  LACM 
45644-1  (8.4  mm  NL),  LACM  45614-1  (12.4  mm 
SL),  LACM  45623-1  (14.0  mm  SL),  and  LACM 
45614-1  (16.0  mm  SL). 

MORPHOLOGY.  Larvae  are  characterized  by 
elongate  body,  preanal  length  of  40-44%  BL,  small 
and  rounded  head  with  a short  snout,  developing 
bifid  nasal  cirri,  and  bifid  orbital  cirri.  Flexion  oc- 
curs after  5.3  mm  and  is  complete  by  10.0  mm,  at 
which  time  the  dorsal  and  anal-fin  rays  develop. 
The  dorsal  spines  begin  to  develop  by  12.0  mm. 

PIGMENTATION.  In  addition  to  the  general 
blennioid  pattern,  the  larvae  of  Acanthemblemaria 
castroi  have  melanophores  that  become  embedded 
during  development  located  above  the  swimbladder 
and  anus;  a melanophore  on  the  mandibular  angle 
by  12.4  mm  SL  (Fig.  7c);  a single  melanophore  on 
the  nape  that  becomes  partially  embedded  with 
growth  (Figs.  7b-e);  and  three  to  four  small  mela- 
nophores that  are  present  during  all  stages  on  the 
ventral  midline  of  the  caudal  peduncle  (Fig.  7a).  No 
pigment  occurs  ventrally  on  the  gut,  or  on  the  pos- 
terior border  of  the  hypurals. 

Acanthemblemaria  atrata 
(Hastings  and  Robertson,  1999) 

Figure  8 

MATERIAL  EXAMINED.  Five  larvae  from  a to- 
tal of  214  collected  in  Chatham  Bay,  Cocos  Island, 

10  ■ Contributions  in  Science,  Number  488 


Costa  Rica,  in  the  size  range  of  4.1-18.4  mm,  are 
illustrated:  LACM  46011-1  (4.1  mm  NL,  5.3  mm 
NL,  6.9  mm  SL,  11.8  mm  SL),  and  LACM  45658- 
1 (18.4  mm  SL) 

MORPHOLOGY.  The  larvae  are  similar  in  mor- 
phology and  meristics  to  those  of  Acanthemble- 
maria castroi,  but  differ  slightly  in  pigmentation. 
The  largest  specimen  (18.4  mm  SL)  has  both  single 
nasal  cirri  and  single  orbital  cirri;  while  larval  pig- 
mentation is  still  present,  heavy  cranial  spination 
appears  along  with  sensory  pores  of  the  mandibu- 
lar, nasal,  occipital,  preopercular,  and  orbital  series. 
The  dorsal-  and  anal-fin  formation  is  similar  to  that 
of  A.  castroi. 

PIGMENTATION.  The  larvae  of  Acanthemble- 
maria atrata  show  the  same  pigment  pattern  as  A. 
castroi,  but  in  addition  exhibit  a band  of  melano- 
phores on  the  posterior  margin  of  the  hypural 
plates.  Further,  one  or  two  melanophores  develop 
ventrally  on  the  anus  (Figs.  8a-c);  these  melano- 
phores disappear  during  development  (Figs.  8d-e). 
A more  complete  larval  series  is  described  for  this 
species,  which  allows  following  of  the  formation 
pattern  of  the  ventral  melanophore  on  the  basip- 
terygium. Two  elongate  melanophores  develop  lat- 
erally in  early  stages,  converging  anteriorly  in  an 
inverted  V-shaped  pattern,  with  the  wings  of  the  V 
fusing  along  the  midventral  margin  (Brogan,  1992). 

Chaenopsis  schmitti  (Boelke,  1957) 
Figure  9 

MATERIAL  EXAMINED.  Only  two  specimens 
collected;  LACM  45614-3  (8.0  and  14.6  mm  SL). 

MORPHOLOGY.  Among  ail  the  blennioids  con- 
sidered here,  this  species  has  the  most  slender  and 
elongate  body.  The  preanal  length  ranges  from  40- 
44%  BL.  The  snout  is  pointed  and  increases  in 
length  with  size.  At  8.3  mm  SL  only  the  posterior 
rays  of  the  dorsal  fin  are  developed,  whereas  anal- 
fin  rays  are  just  forming.  By  14.6  mm,  the  rayed 
portion  of  both  the  dorsal  and  anal  fin  are  formed, 
and  the  dorsal-fin  spines  are  appearing. 

PIGMENTATION.  The  larvae  of  Chaenopsis 
schmitti  possess  single  melanophores  at  the  man- 
dibular angle,  midlaterally  on  the  preoperculum, 
and  on  the  hindbrain.  No  melanophores  are  present 
on  the  caudal  peduncle. 

Stathmonotus  sp. 

Figure  10 

MATERIAL  EXAMINED.  A single  specimen 
was  collected  in  Chatham  Bay,  Cocos  Island,  Costa 
Rica;  LACM  45634-15  (8.3  mm  SL).  Although  the 
genus  has  not  been  reported  there,  the  specimen  can 
be  tentatively  ascribed  to  the  species  Stathmonotus 
culebrai  based  on  meristic  data.  Also,  5.  culebrai  is 
the  only  species  of  the  genus  from  Pacific  Central 
America  (Hastings  and  Springer,  1994). 

MORPHOLOGY.  The  general  shape  of  the  larva 
is  similar  to  that  of  Stathmonotus  stahli  and  S. 
hemphilli  (Brogan,  1992;  Cavalluzzi,  1997),  with  a 

Herrera  and  Lavenberg:  Larval  blennies  from  Galapagos 


a 


e 


Figure  7 Larvae  of  Acanthemblemaria  castroh  (a)  5.3  mm  (LACM  45621-1)  (b)  8.4  mm  (LACM  45644-1)  (c)  12.4  mm 
(LACM  45614-1)  (d)  14.0  mm  (LACM  45623-1)  (e)  16.0  mm  (LACM  45614-1) 


Contributions  in  Science,  Number  488 


Herrera  and  Lavenberg:  Larval  blennies  from  Galapagos  ■ 1 1 


Figure  8 Larvae  of  Acanthemblemaria  atrata:  (a)  4.1  mm  (b)  5.3  mm  (c)  6.9  mm  (LACM  46011-1)  (d)  11.8  mm 
(e)  18.4  mm  (LACM  45658-1) 


small  and  round  head,  and  a prominent  swimblad- 
der.  The  preanal  length  reaches  approximately  50% 
BL  (the  longest  among  chaenopsids);  the  dorsal  fin 
originates  behind  the  level  of  the  pectoral-fin  base 

12  ■ Contributions  in  Science,  Number  488 


(vs.  anterior  to  the  pectorals  in  the  other  three 
chaenopsids);  and  the  number  of  pectoral-fin  rays 
is  low  (9-11  vs.  13-14  in  other  Chaenopsidae).  In 
adult  Stathmonotus  all  dorsal-fin  elements  are 

Herrera  and  Lavenberg:  Larval  blennies  from  Galapagos 


spines  (37-41).  In  the  larva,  the  dorsal  fin  is  com- 
posed by  two  portions,  with  twenty-one  spines  and 
seventeen  soft  rays,  which  indicates  that  the  most 
posterior  spines  of  the  adult  dorsal  fin  are  the  result 
of  secondary  ossification. 

PIGMENTATION.  The  specimen  appears  to  be 
somewhat  bleached  and  some  pigment  may  be 
missing.  The  larva  has  a pair  of  small  ventral  me- 
lanophores  immediately  behind  the  insertion  of  the 
pelvic-fin  rays,  a single  ventral  melanophore  on  the 
gut,  and  a melanophore  over  the  anus.  No  mela- 
nophores  appear  on  the  trunk,  caudal  peduncle,  or 
the  hypural  margins.  The  midventral  melanophore 
at  the  basipterygium  is  not  visible,  but  it  may  be 
embedded,  as  in  Stathmonotus  sinuscalifornici  at  a 
similar  size  (Brogan,  1992).  The  pigmentation  of 
this  specimen  lacks  the  expanded  and  stellate  me- 
lanophores  along  the  ventral  margin  of  the  trunk 
and  gut  of  S.  sinuscalifornici  (Brogan,  1992)  or  the 
lines  of  melanophores  near  the  dorsal  (of  S.  hem- 
philli)  and  ventral  margin  of  the  trunk  of  5.  stahli 
(Cavalluzzi,  1997). 

REMARKS  ON  CHAENOPSID  SPECIES 

An  interesting  character  of  postflexion  larvae  of  all 
species  is  the  presence  of  an  elongate  pigment  patch 
midventral  to  the  basipterygium,  observed  and  il- 
lustrated by  Brogan  (1992)  from  larvae  of  the 


Chaenopsinae  (Hastings  and  Springer,  1994),  such 
as  Emblemaria,  Chaenopsis,  and  Coralliozetus.  The 
pigment  patch  results  from  the  convergence  at  the 
ventral  midline  of  two  more  lateral  and  usually 
elongate  melanophores.  Although  the  ventral  me- 
lanophore is  not  visible  in  large  larvae  of  Neoclinus 
and  Stathmonotus,  it  does  form  in  preflexion  larvae 
and  becomes  embedded  during  the  development 
(Brogan,  1992). 

DISCUSSION 

The  Blennioidei  exhibit  reproductive  features  that 
are  generally  associated  with  low  dispersal  capa- 
bilities such  as  low  fecundity,  demersal  spawning, 
some  form  of  parental  care,  robust  larvae,  and 
short  larval  period.  The  larvae  of  most  families,  ex- 
cluding Blenniidae,  have  few  specializations  (Wat- 
son, 1996),  and  the  number  of  larval  characters 
available  to  study  relationships  is  low.  Cavalluzzi 
(1997)  described  the  larvae  of  two  species  of  Dac- 
tyloscopidae  and  two  of  Chaenopsidae  and  dis- 
cussed the  use  of  life  history  characters  for  eluci- 
dating relationships  within  the  suborder  Blennioid- 
ei. He  found  no  synapomorphies  based  on  larval 
morphology  that  support  the  monophyly  of  the 
suborder.  The  chaenopsid  and  dactyloscopid  larvae 
described  herein,  plus  the  description  of  the  larvae 
of  six  labrisomid  species  (Herrera  and  Lavenberg, 


Contributions  in  Science,  Number  488 


Herrera  and  Lavenberg:  Larval  blennies  from  Galapagos  ■ 13 


1999),  did  not  help  to  resolve  further  synapomor- 
phies.  However,  variation  among  larvae  may  help 
to  elucidate  relationships  within  and  among  fami- 
lies. 

Among  dactyloscopids,  the  larvae  of  the  phylo- 
genetically  primitive  genus  Platygillellus  possess 
plesiomorphic  characters  such  as  paired  cephalic 
melanophores  and  a discontinuous  anterior  profile 
of  the  dorsal  fin.  Larvae  of  the  more  derived  genera 
Myxodagnus,  Dactyloscopus,  and  Dactylagnus, 
which  constitute  a clade  (Doyle,  1998),  possess  a 
single  large  melanophore  on  the  head  and  ventrally 
on  the  gut,  and  a continuous  and  straight  anterior 
dorsal-fin  profile.  The  larvae  of  Gillellus,  another 
derived  dactyloscopid  unrelated  to  the  previous 
clade,  lack  cephalic  melanophores  and  the  anterior 
margin  of  the  dorsal  fin  is  discontinuous.  Unfortu- 
nately, the  larvae  of  the  other  two  genera  of  the 
clade  {Sindoscopus  and  Leurochilus)  have  not  been 
described.  Although  the  absence  of  cephalic  mela- 
nophores may  be  considered  a derived  feature  with- 
in Dactyloscopidae  (e.g.,  also  observed  in  the  prim- 
itive tripterygiids),  it  is  not  possible  to  establish 
whether  the  loss  is  derived  from  a plesiomorphic 
condition  (small  paired  melanophores)  or  a rela- 
tively more  derived  condition  (large  and  single  me- 
lanophores). Nevertheless,  these  characters  are  con- 
sistent with  the  dactyloscopid  relationships  of 
Doyle  (1998). 

Chaenopsid  have  larval  features  that  are  consis- 
tent with  phylogenetic  relationships  obtained  by 
Hastings  and  Springer  (1994)  from  adult  morphol- 
ogy. The  phylogenetically  more  primitive  genus 
Neoclinus  (previously  considered  a labrisomid),  has 
larvae  that  develop  several  melanophores  dorsally 
on  the  head  and  has  a comparatively  short  preanal 
distance  (<39%  SL).  More  derived  chaenopsids 
lack  dorsal  head  pigmentation  and  have  longer  pre- 
anal distances  (40-57%).  Also,  the  phylogenetically 
primitive  Neoclinus  has  a well-defined  pigment  pat- 
tern dorsally  on  the  trunk,  with  melanophores  at 
the  base  of  the  dorsal-fin  spines  and  in  between  the 
pterygiophores  of  the  soft  rays  (Watson,  1996);  this 
feature  is  absent  in  all  remaining  and  more  derived 
chaenopsid  larvae  (Brogan,  1992;  Watson,  1996; 
Cavalluzzi,  1997),  although  it  is  common  in  labri- 
somids  and  in  the  basal  tripterygiids. 

The  larvae  of  all  Chaenopsid  genera  examined  so 
far  possess  an  elongate  melanophore  midventrally 
on  the  basipterygium  that  results  from  the  fusion 
of  two  melanophores  that  develop  laterally  and 
converge  on  the  ventral  midline  (Brogan,  1992).  An 
elongate  melanophore  on  the  basipterygium  is  also 
observed  in  the  labrisomid  Starksiini  Starksia  gal- 
apagensis  (Herrera  and  Lavenberg,  1999).  Based  on 
molecular  evidence,  Stepien  et  al.  (1997)  considered 
the  labrisomids  a paraphyletic  group  and  hypoth- 
esized that  the  tribe  Starksiini  was  more  closely  re- 
lated to  Chaenopsidae  than  were  other  Labrisomi- 
dae.  Although  the  larval  evidence  is  suggestive,  fur- 
ther work  is  needed  to  confirm  the  affinities  be- 
tween Chaenopsidae  and  Starksiini. 

14  ■ Contributions  in  Science,  Number  488 


Among  blennioid  larvae,  other  melanophore 
characters  do  not  seem  to  be  informative  about  re- 
lationships above  genus  level,  although  it  remains 
to  be  determined  whether  they  are  useful  at  lower 
taxonomic  level  (i.e.,  between  species).  For  exam- 
ple, a band  of  melanophores  is  present  in  the  pos- 
terior margin  of  the  hypural  plates  in  the  species 
Hypsoblennius  jenkinsi,  H.  sordidus,  Dactylosco- 
pus pectoralis  fallax,  Acanthemblemaria  atrata, 
and  Malacoctenus  zonogaster,  but  it  is  absent  in 
their  respective  congenerics  H.  brevipinnis,  D.  lac- 
teus,  A.  castroi,  and  M.  tetranemus  (Balbontin  and 
Perez,  1979;  Stevens  and  Moser,  1982;  Herrera  and 
Lavenberg,  1999). 

In  conclusion,  the  phylogenetic  significance  of 
larval  pigment  characters  still  remains  to  be  deter- 
mined. However,  as  suggested  by  Cavalluzzi 
(1997),  it  seems,  that  pigment  characters  may  be 
more  important  for  low  taxonomic  level  (i.e.,  inter- 
or  intrageneric)  than  for  higher  taxonomic  level 
comparisons. 

ACKNOWLEDGMENTS 

We  acknowledge  and  thank  the  University  of  Southern 
California  and  the  Natural  History  Museum  of  Los  An- 
geles County  for  continued  financial  support.  We  also 
wish  to  acknowledge  the  National  Science  Foundation  for 
their  support  of  larval  fish  curation  at  LACM,  which 
made  collections  available  for  study  (NSF  DEB  8814791). 
We  thank  Richard  Feeney  (LACM)  who  assisted  us  during 
our  studies  of  fish  larvae  from  the  Galapagos,  and  C. 
Thacker  (LACM)  for  reading  the  manuscript.  We  thank 
Carol  Stepien  (Cleveland  State  University)  and  Martin 
Cavalluzzi  (Oregon  State  University)  for  their  valuable 
comments  and  suggestions  on  the  manuscript. 

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Received  29  October  1999;  accepted  3 October  2000. 


Contributions  in  Science,  Number  488 


Herrera  and  Lavenberg:  Larval  blennies  from  Galapagos  ■ 15 


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