Description of the Male of Diplocentrus lourencoi (Scorpiones, Diplocentridae)

6 Pages·1997·5.2 MB·English

by  Kari J Mcwest

1997. The Journal ofArachnology 25:251-256
DESCRIPTION OF THE MALE OF DIPLOCENTRUS LOURENCOI
(SCORPIONES, DIPLOCENTRIDAE)
Kari J. McWest: Department of Life, Earth, and Environmental Sciences; West Texas
A&M University, WTAMU Box 808, Canyon, Texas 79016 USA
ABSTRACT. The male of Diplocentrus lourencoi Stockwell 1988 is described and illustrated from a
specimen collected westofSan Pedro Sula, Honduras, andcomparedtotheholotypefemale andthemales
of other Diplocentrus Peters 1861 in the region. The hemispermatophore is described, illustrated, and
compared to otherDiplocentrus in the region. Unique new characters on the male, posterolateral recesses
on tergite VII, are described and illustrated. New descriptive information is given forthe holotype female.
Complete measurements and morphometries are given for the male and female. A comparative diagnosis
is offered based on this new information.
The original description of Diplocentrus more diagnostic characters forthe genus atthe
lourencoi Stockwell 1988 was based on a sin- species level than do female characters
gle adult female from Rio Santa Ana Canyon (Francke 1977).
(3500 ft.), San Pedro Sula, Departamento Cor- Due to the brevity of the original descrip-
tes, Honduras, collected during the Field Mu- tion it became necessary to examine the fe-
seum Expedition into Central America in the male holotype. Upon exanfination of the ho-
spring of 1923. Recently, Thomas G. Anton lotype, the drawings of the female pedipalp
of the Field Museum (FMNH) discovered un- chela in the original description were found to
determined scorpion material that included an depict inaccurately the nature ofthe chelal re-
additional specimen from the expedition that ticulation, granulation, and keel structure. The
was not studied previously. This specimen is pattern of chela reticulation and texture ob-
an adult male collected by K. Schmidt and L. served in the holotype female is extremely
Walters on 1 April 1923 at “Mt. Camp, 4500 similar to that seen in the male, which is here-
ft. EL, W. ofSan Pedro Sula, Honduras,” sev- in described and illustrated. In addition, the
eral days after the female holotype was col- notable slenderness of the chelicerae and
lected. (According to Mr. Anton [pers, length of the cheliceral fingers of Diplocen-
comm.], “Mt. Camp” refers to the campsite trus lourencoi were not included in the orig-
location and not a geographic place name.) inal description: cheliceral morphometries
Examination of the holotype female was nec- have been found to have diagnostic impor-
tance in diplocentrid scorpions (Francke
essary to confirm that this male specimen is
1977). Complete measurements for the holo-
referable to D. lourencoi. This specimen
brings the total number of reported diplocen- type female are published here for the first
time.
trids from Honduras to a mere 12 individuals
Nomenclature and mensuration essentially
assignable to four species in two genera: Di-
follow that of Stahnke (1970), except that
plocentrus coddingtoni Stockwell 1988, D.
cheliceral measurements and carinal terminol-
santiagoi Stockwell 1988, D. lourencoi, and
ogy are after Francke (1975, 1977) and trich-
Didymocentrus krausi Francke 1978. obothrial terminology is after Vachon (1974).
Because the male of this species is previ-
ously undescribed and distinct sexual dimor- Diplocentrus lourencoi Stockwell 1988
phism in diplocentrids is well documented, it Diplocentrus lourencoi Stockwell 1988: 161-163,
is important that comparisons are made to figs. 19-24.
complete the diagnosis of the species and to —
aid in separating D. lourencoi from related Type data. Holotype female from Rio
species. Male morphology tends to provide Santa Ana Canyon (3500 ft.), San Pedro Sula,
251
252 THE JOURNAL OF ARACHNOLOGY
Departamento Cortes, Honduras, 21 March submedian carinae vestigial, smooth, provided
1923 (K. Schmidt and L. Walters), Capt. Field with four pairs of setae; lateral carinae weak,
Mus. Exped., deposited in the Field Museum, smooth, provided with five pairs of setae.
Chicago; examined {Note: The original data Hemispermatophore: Lamelliform; inner
label with the specimen does not indicate San margin of median lobe with a moderate ridge
Pedro Sula or Departamento Cortes: this in- with four teeth. Distal lamina not broad, ta-
formation was thoughtfully provided in the pering only at distal end (Figures 3-5).
original description by Stockwell, apparently Metasoma: Segments I-IV: Dorsolateralca-
after a thorough investigation ofHonduras ge- rinae moderate, granular, increasing in
ography). — strength on distal segments. Lateral suprame-
Description of male. Coloration (in al- dian carinae on I-IV strong, on I-II smooth
cohol): Carapace dark orange brown to ma- to granular, on III-IV granular throughout.
hogany with weak underlying marbling of Lateral inframedian carinae on I-III moderate,
light patches. Tergites dark orange brown to smooth to granular; on IV (Fig. 6) represented
mahogany, infuscate. Metasoma dark orange by an irregular row of granules. Ventrolateral
brown, with each segment gradually darker carinae on I moderate, smooth; on II-IV
distally; dorsal keels at least proximally ni- weak, granular. Ventral submedian carinae on
grocarinate; telson dark orange brown, grad- I and II weak, smooth to granular; on III mod-
ing to light yellow brown at subaculear erate, smooth on proximal one-half, vestigial
tubercle. Venterofprosomareddish brown be- with irregularly scattered granules on distal
coming yellow brown laterally with faint in- half; reduced on IV to two narrowly separated
fuscation; genital opercula, pectines, and basal irregular rows of granules on proximal two-
piece yellowish. Stemites II-VI light orange thirds. Intercarinal spaces feebly reticulate.
brown to light yellow brown; stemite VII Segment V: Dorsal surface densely finely
slightly darker. Chelicera manus light yellow granular medially with coarsergranulation lat-
brown becoming slightly darker distally with erally; dorsolateral carinae moderate, densely
faint reticulate pattern proximally; fingers yel- moderately granular; lateromedian carinae
lowish, with teeth somewhat transparentunder present only on anterior two-thirds, strong,
magnification, appearing light orange brown. granular; lateral intercarinal surfaces feebly
Pedipalp external surfaces deep mahogany reticulate, smooth distally (Fig. 6); ventrolat-
gradually becoming lighter distally to light eral, ventromedian, and ventral transverse ca-
red-brown fingers; internal surfaces light yel- rinae moderate to strong with subconicalgran-
low brown atdorsal lobebecoming darkerdis- ules, with cluster of seven ventromedian
tally. Legs darkyellow brown proximally with granules beyond ventral transverse row.
marbled pattern, distal segments light yellow- Telson: Ventral surface hirsute with short,
ish. white microchaetes outnumbering light-red
Prosoma: Carapace only slightly longer setae; densely covered with extremely fine
than posterior width; length/width ratio 1.05. granules, increasingly coarser ventrally and
Surface feebly reticulate. Anterior margin of proximally (Fig. 6). Subaculear tubercle
carapace and anterior median furrow moder- densely hirsute, strong, laterally compressed,
ately coarsely granular (Fig. 1); remainder of subconical in profile, with three pairs oflong,
carapace with dense fine granulation inter- light-red setae.
spersed with coarser granules. Sternum with Chelicerae: Dentition as in Fig. 7. Smooth
14 setae; each genital operculum with seven and relatively long, slender; fixed finger short-
setae. Coxosternal region finely punctate, er than chela width (0.82X); movable finger
somewhat lustrous; coxae sparsely setose. subequal to chela length (0.93X). Other ratios
Mesosoma: Tergites I-VI with very dense in morphometric ratios section. Ventral brush-
fine granulation, shagreened. Tergite VII es thick, long. Teeth largely transparent with
weakly bilobed posteriorly with moderate to only slight coloration on di ofmovable finger;
coarse granulation (Fig. 2). Pre-posterolateral di and de not in apposition (Fig. 8).
recess moderate, shallow; posterolateralrecess Pedipalps: Trichobothria pattern Type C,
strong, deep (Fig. 2). Pectinal tooth count 9- orthobothriotaxic (Vachon 1974). Femur:
10. Stemites III to VI finely punctate and Wider than deep, with dorsointemal and ven-
somewhat lustrous, smooth. Stemite VII with trointemal carinae strong, granulose; dorsoex-
McWEST—DIPLOCENTRUSLOURENCOIMALE DESCRIPTION 253
—
Figures 1-8. Morphology of male of Diplocentrus lourencoi Stockwell. 1, Dorsal aspect of anterior
region ofcarapace; 2, Oblique view ofright lateral aspect oftergite VII, showing posterolateralrecesses,
ppr — pre-posterolateral recess; pr = posterolateral recess; 3, Dorsal aspect ofright hemispermatophore;
4, Detail of inner margin of median lobe, showing positions of teeth; 5, Ventral aspect of right hemi-
spermatophore; 6, Left lateral aspect of metasomal segments IV, V, and telson; 7, Dorsal aspect of left
chelicera; 8 External aspect of left cheliceral movable finger.
,
temal carina strong, irregularly granulese on toward internal face. Patella: Dorsomedian
basal two-thirds, moderately granulose on dis- keel moderate, smooth; dorsoextemal keel
tal third; ventroextemal carina vestigial to ob- moderate, irregular, smooth to granular (Fig.
solete, moderately granulose at proximal one- 10); ventrointemal keel moderate, smooth to
fifth. Dorsal surface of femur flat, with mod- coarsely granular; ventromedian keel reduced,
erate and coarse granules scattered mostly for with scattered fine to moderate granules; ven-
%
of length, dorsomedian seta situated cen- troextemal keel moderate, smooth, distal third
trally (Fig. 9). Internal face covered with comprised of strong reticular costae. Chela:
coarse granules, several ofthese granulesrath- Palm (Fig. 11) with distinct reticulate pattern
er large. Ventral surface finely granulose ex- formed by weak, unpigmented costae; costae
ternally, gradually becoming coarsely granular lustrous, interspersed with moderate to coarse
254 THE JOURNAL OF ARACHNOLOGY
—
Figures 9-12. Morphology of the pedipalps ofDiplocentrus lourencoi. 9, Dorsal aspect ofright ped-
ipalp femur, dms = dorsomedian seta; 10, Dorsal aspect of right pedipalp patella; 11, External aspect of
right pedipalp chela; 12, Dorsal aspect ofright pedipalp chela.
granules; intercostal areas extremely finely 5.0/3.4; IV L/W, 5.7/3.0; V L/W, 7.4/2.7. Tel-
granular (shagreened); dorsal margin (Fig. 12) son: vesicle L/W/D, 4.4/2.8/2.4; aculeus L,
moderately granular basally to strongly, 1.5. Pedipalps: Femur L/W, 6.2/2.2; patella
coarsely granular to base of fixed finger; dig- L/W, 6.6/1.2; chela L/W/D, 12.8/3.2/5.0; fixed
ital keel moderate and smooth for most of finger L, 6.2; movable fingerL, 8.4; palm (un-
length, granulose and fading at trichobothrium derhand) L, 4.4. Chelicerae: Manus L/W, 2.01/
Dt\ dorsal and external secondary keels re- 1.35; fixed finger L, 1.11; movable finger
duced, wide, and moderately granulose; outer length (Hide: 1.86/1.47. —
surface above imaginary line between tricho- Comparison with holotype female. ^The
bothria Esb and Est reticulate, below line male is similar in appearance to the female
granulose; ventral keel strong, coarsely gran- with notable exceptions. Following are the
ular; ventrointemal keel moderate, granulose; morphometric ratios, with female ratios in pa-
internal surface of palm smooth, feebly retic- rentheses. Pedipalp proportionately longer and
ulate with all keels greatly reduced and inter- more slender, pedipalp femur length/width,
spersed with fine to moderate granules. Fixed 2.82 (2.35); patella length/width, 3.14 (2.20);
and movable fingers punctate, setose. chela length/width, 4.00 (3.43); length/depth,
Legs: Tarsomere II spine formula 4/5 4/5: 2.56 (2.26); metasomal segment II slightly
5/5 5/5: 5/5 5/5: ?/? 5/5. shorter, length/width, 1.18 (1.22); metasomal
Measurements: Total L, 53.8; carapace segment V considerably longer, length/width,
L/W, 6.5/6.2; mesosoma L (specimen fragile 2.74 (2.38). (Other ratios provided below.)
and longitudinally compacted), 14.5; metaso- Pedipalps: Granules noticeably more reduced,
ma L, 26.9; telson L, 5.9. Metasomal seg- especially on dorsal surfaces of femur and
ments: I L/W, 4.1/3.8; II L/W, 4.7/4.0; IIIL/W, chela, rarely encountered in diplocentrid sys-
McWEST—DIPLOCENTRUSLOURENCOIMALE DESCRIPTION 255
tematics but known to occur in Diplocentrus V L 1.14 (1.19), fixed finger L/carapace L ra-
rectimanus Pocock (Francke 1977). Dorsal tio 0.95 (0.81). —
surface of femur flat on male, distinctly con- Comparative diagnosis. The female of
vex on female. Reticulation of chela less dis- Diplocentrus lourencoi was comparedto other
tinct. Telson distinctly less granulose. Female Diplocentrus in the region by Stockwell 1988.
slightly lighter in color, being a more yellow- Comparisons of the male with other species
ish brown than reddish brown, keeping in are based on the original descriptions and il-
mind that the specimens are old and that some lustrations (i.e., the specimens were not ex-
integumental separation has occurred in the amined). The hemispermatophore of D. lour-
female. Integument of carapace and tergites encoi does not bear spines on the anterior
shagreened in male, somewhat lustrous in fe- margin of the median lobe as do those of D.
male. steeleae and D. ornatus. The hemispermato-
Tergite VII: The female has a more typi- phore of D. coddingtoni differs by lacking
cally shaped disc. The male, on the other denticles on the inner margin of the median
hand, has strong, deep, posterolateral recesses lobe. The pedipalp chela of D. lourencoi dif-
(Fig. 2). Upon further comparisons with sev- fers from that of D. omatus by its greater
eral species of Diplocentrus, Bioculus Stanke width/depth ratio (0.64 versus 0.43) and great-
1968, Didymocentrus Kraepelin 1905, and er length/depth ratio (2.56 versus 2.16); it
Nebo Simon 1878 (made available by W. Da- differs from D. coddingtoni by its longer,
vid Sissom and Chad M. Lee), it became ev- more robust chela (length/depthratio 2.56 ver-
ident that the extreme depth of this feature is sus 2.98; chela length/fixed finger length ratio
unique to at least this male specimen. Unfor- 2.04 versus 2.44).
tunately, only a single male specimen of D. ACKNOWLEDGMENTS
lourencoi is known so the utility of this fea- I wish to thank my good friend Tom G. An-
ctuornefiirnmadtiipolnoceanstrnidewsysmtaetmearitailcsawciclulmurleaqtueisr.e ton (formerly an assistant at EMNH) for no-
ticing undetermined scorpion material in the
Future descriptions should, therefore, include EMNH
collection and subsequently reporting
a brief statement regarding this feature.
such specimens to W. David Sissom and me.
Measurements ofholotypefemale: Total L,
His shared knowledge ofthe 1923 herpetolog-
50.9; carapace LAV, 6.3/6.4; mesosoma (dis- ical Field Museum Expedition into Central
tended) L, 16.6; metasoma L, 22.3; telson L,
America was also very helpful. Thanks are
5.7. Metasomal segments: I L/W, 3.5/3.4; II also due to A1 Newton for granting loans of
L2./9W;,V3.L9//3W.,2;6.II2I/2.L6/.W,Tel4.so1n/3:.1V;esIiVcleL/LW/,W/4.D6,/ tihpisP.mPaatrerriilalloa(nEdMtNoHD)anfioerlpSruempamreirnsg tahnedlPohainls-
4.4/2.8/2.3; aculeus L, 1.3. Pedipalps: Femur of such material and the holotype female of
L/W, 5.4/2.3; patella L/W, 5.5/1.7; chela L/W/ Diplocentrus lourencoi. I also wish to thank
D, 12.0/3.5/5.3; fixed finger L, 5.1; movable Chad M. Lee for discussions on diplocentrids
finger L, 7.4; palm (underhand) L, 4.6. Che- and for his reviews of the working drafts of
licerae: Manus L/W, 1.95/1.47; fixed finger L, the manuscript. William M. Burrell of the
1.11; movable finger length dUde: 1.89/1.53. Dept, of Fine Arts at Amarillo College, Am-
Morphometric ratios: (Female ratios are in arillo, Texas is greatly appreciated for his ar-
parentheses.) Carapace L/W 1.05 (0.98); tistic suggestions and support. Special thanks
metasoma II L/W 1.18 (1.22); metasoma III are reserved for Dr. Sissom for obtaining the
L/W 1.47 (1.32); metasoma V L/W 2.74 specimens and passing them along to me for
(2.39); cheliceraWchela L/W 1.49 (1.33), fixed examination. He also allowedme to perusehis
finger L/chela ratio 0.82 (0.76), movable private collection and other specimens in his
finger L/chela L ratio 0.93 (0.97); pedipalp fe- care. I am extremely grateful for his guidance
mur W/D (at dorsomedian seta) 1.22 (1.15), through the course of this study and for his
chela fixed finger L/carapace L 0.95 (0.81), suggestions and criticism while reviewing the
movable finger L/carapace L 1.29 (1.17), che- various drafts of the manuscript. Petra Sier-
la L/W 4.00 (3.43), chela L/D 2.56 (2.26), wald graciously furnished valuable sugges-
chela W/D 0.64 (0.66), movable finger L/che- tions incorporated into the manuscript. Victor
la D 1.68 (1.40), movable finger L/metasoma Fet and Emilio Maury kindly reviewed the
256 THE JOURNAL OF ARACHNOLOGY
manuscript. This study was supported with a Stahnke, H.L. 1970. Scorpion nomenclature and
West Texas A&M University Research Assis- mensuration. Entomol. News, 81:297-316.
Stockwell, S.A. 1988. Sixnew speciesofthegenus
tantship.
Diplocentrus Peters fromCentral America(Scor-
LITERATURE CITED piones, Diplocentridae). J. ArachnoL, 16:153-
175.
Francke, O.E 1975. Anew species ofDiplocentrus Vachon, M. 1974. Etude des caracteres utilises
fromNewMexicoandArizona(Scorpionida,Di- pour classer les families et les genres de Scor-
plocentridae). J. ArachnoL, 2:107-118. pions. (Arachnides). Bull. Mus. Nat. Hist. Nat.,
Francke, O.E 1977. Scorpions ofthe genus Diplo- Paris, 3nt smes. No. 140, ZooL, 104:857-958.
centrus from Oaxaca, Mexico (Scorpionida, Di- Manuscript received 5 September 1996, revised 15
plocentridae). J. ArachnoL, 4:145-200. February 1997.