HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 203 Genus Dentigryps Wilson

Diagnosis.

— ^Fourth

^thoracic leg-bearing

segment and

genital seg-

ment

fusedinfemale,covered

by

single, dorsalplate. Lunulesabsent, sternal furca present; fifth legs of female elongate, conical, spinelike processes protruding from genital segment.

Remarks.— The

genus

was

established

by

Wilson (1913) on the characteristicspresented

by

the female ofD. Curtus Wilson, 1913, the type-species of the genus.

With

the description of the

new

species below, the second species

known

^for thegenus, the diagnosis hasbeen modified slightly.

Dentigrypsbifurcatiis,

new

species Figures 17a-c,e-k,m-q, 18a-c,€,f

Material. —

Nonovigerous adult female (holotype,

USNM

105094) taken

by

author fromside ofspecimen ofAcanthurus olivaceousBloch

and

Schneider given toauthor

by Mr.

SpencerTinkerfromcollections of

Honolulu Aquarium. Mature male

(allotype,

USNM

^105095) ^col-

lected

by

author

from

caudal fin of specimen of

Naso

hexacanthus (Bleeker) captured in fish trap

between Diamond Head and Koko Head, Oahu,

Hawaii,

by Samuel

Kaolulo.

Mature

female (paratype,

USNM

^105096) ^collected

^by

^Dr.

John

Randall from epidermis of specimen of Acanthurus triostegus sandvicensis Streets captured in

unknown

locality

on Oahu,

Hawaii.

Measurements.- — ^Holotype

^female:

Length from

anterior end to posterior

end

of caudal rami, excluding setae, 3.50

mm.

Greatest length of cephalothorax, including frontal region, 2.44

mm,;

greatest width, excludingmarginalflanges,2.30

mm.

Greatest lengthoffused fourth thoracic leg-bearing

segment and

genital

segment

0.70

mm.;

greatestwidth ofgenital

segment

1.19

mm.;

lengthof left genitalseg-

ment

spine0.78

mm.

Tip ofrightspine broken.

Allotypemale:

Length

fromanterior

end

to posteriorend ofcaudal rami, excluding setae, 1.97

mm.

Greatest length of cephalothorax, including frontal region, 1.48

mm.;

greatest width, excludingmarginal flanges, 1.48

mm.

Greatest length of fourth thoracic leg-bearing

segment and

genitalsegment, ^excludingsixth leg projections,0.50

mm.

(measurement

taken

on

ventral surface); greatest width of genital

segment

0.39

mm. ^Length

^of ^projecting ^fifth ^legs, ^excluding ^setae,

0.18

mm.

Paratype female:

Length from

anterior end to posterior end of caudal rami, excluding setae, 2.85

mm.

Greatest length of cephalothorax, including frontal region, 2.07

mm.;

greatest width, excluding marginal flanges, 1.93

mm.

Greatest length of fused fourth thoracic

204 PROCEEDINGS OF THE NATIONAL MUSEUM

^vol. ¹¹⁵

leg-bearing

segment and

genital

segment

0.59

mm.;

greatest width of genital

segment

1.07

mm.;

length of genital

segment

spines 0.66

mm.

Description.-

—

_^Body of female with large, yellowish blotches in irregularpatternin alcohol;eye spots yellowish orange.

Body

male

yellowish in alcohol, with red spots scattered over surface; eyes as in female,

Cephalothorax of holotype female specimen ovoid, frontal region small, with thin,

membranous

flange along anterior margin; frontal region separated from cephalothorax

by

distinct, trilobed groove,

median

lobe

much

larger than lateral lobes. Lateral margins of cephalothorax with narrow,

membranous

flange. Posterior sinuses distinct, U-shaped, with

two

small,

membranous

flaps attached along lateral

and

anterior margins, one extending ventrally,other dorsally.

Inner

margin

ofposterior sinusescontinuous with posteriorlateral

and

posteriormarginsof

median

cephalothoracicregion.

Median

cephalothoracic region extending slightly posterior to posterior lateral extensions of lateral cephalothoracic regions; middle of posterior margin slightlyconcave. Dorsal groovesofcephalothoraxdistinct,

H

-shaped

;

anterior portion of grooves terminating blindly posterior to eyes, cross groove, in middle of cephalothorax, curving anteriorly, not as distinct as longitudinal grooves. Lateral strengthening regions extending from just anterior to junction of cross

and

longitudinal grooves laterally

and

posteriorly, terminating just inside lateral margins of cephalothorax.

Eyes

^small, situated in anterior third of cephalothorax, inner margins touching on

median

longitudinal axis of

body

^(fig. 17a).

Fourth

thoracic leg-bearing

segment and

genital

segment

fused in female, covered

by

single, dorsal plate. Fourth thoracic leg-bearing

segment more

distinct than in D. curtus, genital

segment

not be- ginning under posterior portion of cephalothorax as in D. curtus but slightly behind it. Genital

segment

expanded, lateral areas broadly rounded, middle of posterior margin concave, not convex as in D.

curtus, posterior lateral margins without single, small, pointed pro- trusion present in D. curtus (figs. 17c,d). Fifth legs visible as long, acuminate, unjointed, spinelike projections from ventral posterior lateral surface of genital segment. Spinelike projection with three small,

plumose

setules, one

on

proximallateral surface, one

on

ventral medialsurface, one on ventral distal surface (figs. 17c,d).

Abdomen

of female one-segmented, attached to posterior surface of genital segment, not ventral surface as in D. curtus.

Width

abdomen

approximately

same

as length.

Abdomen

without posterior lateral extensions found in D. curtus (figs. 17c,d).

Cephalothorax of allotype

male

similar to that of female except frontalregion withflatter anterior margin. Region of third thoracic

HAWAIIAN

ACANTHtJRID CALlGOIDS

— ^LEWIS 205

01mm.

d

Figure 17.

—

Dentigryps bifurcatus, newspecies (holotype female, allotype male): a,dorsal viewoffemale;b,dorsalviewofmale;c,ventralviewof posteriorendofgenitalsegment,

fifth leg,abdomen, andcaudalramusoffemale;(J,ventralviewof posteriorendof genital segment,fifth leg,abdomen,and caudalramusoffemale specimenofZ).curtus);e,ventral viewof posteriorendofgenitalsegment, fifthandsixthlegs,abdomen, andcaudalramus ofmale;/, antennule;_g,femalesecond antenna; h, male second antenna;i, mandible;;, postantennalprocess;k,postoral process of female;(/,postoral process of femalespecimen ofD.curtus);m,postoral process of male;n, maxilla;o,maxilliped of female;_p,maxilllped ofmale;_q,sternalfurca.

206 PROCEEDINGS

THE NATIONAL MUSEUM

^vol. ⁱⁱ⁵

leg-bearing

segment

of thorax, contained in cephalothorax, extended over fourth thoracic leg-bearing segment.

Fourth

thoracic leg- bearing

segment

partially visible dorsally, separated from genital

segment by

distinct line of division; fourth thoracic leg-bearing seg-

ment and

^genital

segment

not covered

by

single, dorsal plate as in female. Fifth legs visible as conical projections of lateralmargins of genital segment, projections appearing as series of three overlapping, lappet-like processes, each bearing single, terminal,

plumose

seta.

Sixth legs visible as conical projections of posteriorlateralmargins of genital segment, lappet-like processes visible

on

fifthlegs also present

on

sixth though not as distinct; sixth legs with three terminal, plu-

mose

setules (figs. 17b,e).

Antennule

male and

female two-segmented, excluding frontal plate, attached to ventral surface of both cephalothorax and frontal region just medial to lateral margins of frontal region. First seg-

ment

broad proximally, tapered

on

margin

narrow

distal end; greatest length one

and

one-fourth times greatest width.

An-

terior

margin

of first

segment

with fifteeen plumose setae.

Second segment

slightly

than half length of first, with

naked

seta on middle of posterior

margin and

naked

setae

from rounded

distal end (fig. 17/).

Second

antenna of holotype female three-segmented, attached posterior

and

medial to antennule base. First

segment

short, broad, forming articular surface for second segment; with triangular, posteriorly directed process.

Second segment

well developed, greatest width equalto greatestlength,withsmalladhesion

pad on

innerdistal surface.

Second segment

with several small, heavily chitinized de- pressions

on

distal

margin

serving as articular surfaces for third segment. Third

segment

with terminal, clawlike process; division

between segment and

process indistinct. Terminal process curved sharply inwards distally.

Length

of third

segment and

terminal process greater than that of second segment; third

segment

without accessory processes (fig. 17^).

Second

antenna of allotype

male

three-segmented; first

segment

long,

narrow

proximally,

expanded

medially, tapered distally; distal

end

with projecting, lobate articular process, without posteriorly projecting processoffemale. First

segment

with adhesion surface on outer distal half of segment.

Second segment

strongly developed, swollen proximally,

narrow

distally. Inner surface of second seg-

ment

forming adhesion surface proximally; with small, swollen adhesion surface projectingfrom inner distal surface;both adhesion surfaces on inner surface connected

by

irregular ridges. Third

segment

short, with

compound

terminal process consisting of simple, curved, spinelike structure with bifurcate process fused to anterior lateral

Dalam dokumen Proceedings of the United States National Museum (Halaman 67-71)

HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 203 Genus Dentigryps Wilson

— Fourth

segment and

ment

by

Remarks.— The

was

by

by

With

new

known

new

Material. —

USNM

by

and

by Mr.

Honolulu Aquarium. Mature male

USNM

by

from

Naso

between Diamond Head and Koko Head, Oahu,

by Samuel

Mature

USNM

by

John

unknown

on Oahu,

Measurements.- — Holotype

Length from

end

mm.

mm,;

mm.

segment and

segment

mm.;

segment

mm.;

ment

mm.

Length

end

mm.

mm.;

mm.

segment and

mm.

(measurement

on

segment

mm. Length

mm.

Length from

mm.

mm.;

mm.

204 PROCEEDINGS OF THE NATIONAL MUSEUM

segment and

segment

mm.;

segment

mm.;

segment

mm.

—

Body

male

membranous

by

median

much

membranous

two

membranous

and

margin

— ^Fourth

^by

Measurements.- — ^Holotype

mm. ^Length

— ^LEWIS 205