DESCRIPTION OF THE FEMALE OF ACROPSOPILIO CHOMULAE (GOODNIGHT & GOODNIGHT 1948) FROM CHIAPAS, MEXICO (OPILIONES, CADDIDAE, ACROPSOPILIONINAE)

2004·4.4 MB·English

by  William A Shear

2004. The Journal of Arachnology 32:432-435
DESCRIPTION OF THE FEMALE OF ACROPSOPILIO CHOMULAE
(GOODNIGHT & GOODNIGHT FROM CHIAPAS, MEXICO
1948)
(OPILIONES, CADDIDAE, ACROPSOPILIONINAE)
William A. Shear: Department of Biology, Hampden-Sydney College, Hampden-
Sydney, Virginia 23943 U.S.A.
ABSTRACT. The tiny caddid harvestmanAcropsopilio chomulae (Goodnight& Goodnight 1948), from
Chiapas, Mexico, has been known only from the immature holotype Mature females are described from
.
specimens taken near the type locality. The absence ofspermathecae in the ovipositor makes it likely that
the species is parthenogenic.
RE8UMEN. Hastael momento, los unices dates disponibles delpequeno opilionAcropsopiliochomulae
(Goodnight & Goodnight 1948) de Chiapas (Mexico) proceden del estudio del holotipo, un ejemplan
inmaduro. En este trabajo se describen herobras maduras procedentes de cerca de localidad tipica. La
ausencia de espermateca en el oviscapto sugiere que la especie es partenogenetica.
Keywords: North America, harvestman, parthenogenesis
In my 1975 revision ofthe harvestman fam- Casas (92°36 W, 16°42'N), 25 August 1966,
ily Caddidae (Shear 1975), I was unable to W. & J. Ivie (AMNH).
treat the interesting species Acropsopilio cho- Description of female.---Total length, 1.14
mulae (Goodnight & Goodnight 1948) in de- mm; width of eye tubercle, 0.42 mm. Eye tu-
tail because the immature holotype was the bercle occupies entire propeltidium when seen
only available specimen. Having describedthe from above, projecting considerably over che-
species as Caddo chomulae in 1948, Good- licerae, deeply impressed in median line. Eyes
mm
night and Goodnight later (1950) mentioned 0.17 in diameter, slightly protruding, cir-
collecting numbers of mature individuals, but cular. Free thoracic tergites (meso- and meta-
when I enquired in the early 1970s, they could peltidium) only slightly distinct when seen
not locate this material, and the present from above (for general form of body, see
whereabouts of these specimens remains un- Shear 1975, fig. 10). Body soft, not heavily
known. However, the American Museum of sclerotic, devoid of spines or tubercles. La-
Natural History (AMNH) has a small collec- brum triangular, pointed, large. Coxae and en-
tion ofthis species made near the type locality dites as in A. boopis (Crosby 1904) (Shear
by Wilton and Jean Ivie. I take this opportu- 1975, fig. 7), but eedites of coxae II in some
nity to describe these specimens. specimens entirely separating endites ofcoxae
TAXONOMY I from their coxae. Genital operculum large,
broad, bluntly pointed. Sternum not sclero-
tized. Spiracles vestigial, closed.
Family Caddidae Banks 1892
Subfamily Acropsopilioninae Roewer 1923 Palpus (Fig. 1) longer in proportion to body
& length In mature specimens than in juvenile
Acropsopilio chomulae (Goodnight
holotype. Palpal trochanter with one promi-
Goodnight 1948)
nent seta and several smallerones. Femur0.67
Figs. 1, 2 mm mm
long, 0.10 wide, with characteristic
Caddo chomulae Goodnight & Goodnight 1948: group of three seta-bearing tubercles near
201
. base, single seta-bearing tubercle nearmidliee
Acropsopilio chommulae (sic): Ringuelet 1962:79.
Acropsopilio chomulae Shear 1975:79. and at femoral apex on mesal side, bmshlike
: group of small setae on lateral side about two-
— mm
Material examined. MEXICO: Chiapas thirds from base of femur. Patella 0.34
: mm mm
8 $ from 4 miles east ofSan Cristobal de las long, 0.10 wide; tibia 0.32 long, 0.10
,
432
—
SHEAR ACROPSOPILIO CHOMULAE FEMALE 433
mm
wide, with 10-12 glandular setae ven- and tibia, from A. venezuelensis Gonzales-
mm mm
trally. Tarsus 0.25 long, 0.10 wide; Sponga 1992 in having the apical spined tu-
with small, immobile, vestigial claw, 20-24 bercle of the palpal femur close to the distal
glandular setae ventrally. end rather than set back about 1/3 the length
Legs relatively short and thin, leg IV much of the femur, from A. chilensis in having the
the longest. Femora I-IV 0.38, 0.57, 0.50, palpal tarsus shorter than the tibia, and from
mm
0.76 long respectively; tibiae I-IV 0.25, A. neozealandiae (Forster 1948) in stronger
mm
0.30, 0.34, 0.44 long respectively. spined tubercles at the palpal femur base. In
Ovipositor (Fig. 2) short, membranous, overall appearance and especially palpal mor-
with two rings marked by apical transverse phology, chomulae most closely resembles
rows of setae, valves irregularly setose, sen- neozealandiae.
sillum single, apically bifurcate seta. Seminal Recently, 1 briefly summarized the bioge-
receptacles not detected. ography and evolutionary relationships of the
Color light brown, darker on abdominal acropsopilionines (Shear 1996). Writing that
dorsum, eye tubercle pale tan, eyes broadly paper, I was not aware of the description by
ringed in black, palpus with femur and patella Gonzalez-Sponga (1992) of Acropsopilio ve-
striking pure white, tibia and tarsus dark nezuelae from northern South America. This
,
brown, legs medium tan. species provides a biogeographic linkbetween
A. chilensis Silvestri 1904 in southern South
DISCUSSION
America and the northern hemisphere species
As implied from an earlier description of A. chomulae and A. boopis. Gonzalez-Spon-
the juvenile holotype, A. chomulae is a dis- ga’s discovery, the finding of Austropsopilio
tinct species. It differs from A. boopis in hav- sudamericanus Shultz & Cekalovic 2003 in
ing no spined tubercles on the palpal patella Chile and Argentina (Cokendolpher & Maury
434 THE JOURNAL OF ARACHNOLOGY
1990; Shultz & Cekalovic 2003), and the de- (Maury et al. 1996; these authors evidently
scription of Hesperopilio mainae Shear 1996 did not check for spermathecae). A single
from Western Australia (Shear 1996) remind male is known for A. venezuelae Gonzalez-
us that much fundamental data remains to be Sponga 1992 (Gonzalez-Sponga 1992), and
collected concerning these minute, relictual, there is always the possibility that males of
hard-to-find harvestmen. The trans-Pacific the “females only” species are very short-
distribution of several of the genera makes lived, occupy a different habitat or simply
these animals important in establishing zoo- have not been collected. I believe that parthe-
geographical connections between Australia nogenesis for A. chomulae represents the best
and temperate southern South America. hypothesis, though it is difficult to prove a
Ovipositors ofAcropsopilio chomulae were negative-the complete absence ofmales. Only
mounted temporarily on microscope slides laboratory rearing can answer the question de-
and examined under oil immersion and No- finitively, and the caddids, with their require-
marski differential interference contrast, on an ments for cool, moist conditions, are very dif-
Olympus BX50 microscope. No spermathecae ficult to keep alive in captivity.
were seen, as is the case with A. boopis. The A thorough comparative study of the male
absence ofthese structures makes it likely (but genitalia in the caddoids is lacking, and a re-
&
not certain; see Bertani Silva Junior 2002) markable range of variation in basic design is
that A. chomulae is parthenogenic. Partheno- present. Most of the species for which penes
genesis is common in the Caddidae, but sex- have been illustrated have organs with heavily
ual species also occur, in a complex mosaic. sclerotized, movable macrosetae Hesperopi-
(
Caddo agilis Banks 1892 females lack sper- lio mainae Shear is an exception). The spiny
mathecae, and only three males have ever penes are closest in form to those of the Neo-
been found among hundreds of specimens pilionidae, which, like the caddoid penes, fea-
&
(Gruber 1974; Suzuki Tsurusaki 1983). ture movable macrosetae. Neopilionids also
Caddo pepperella Shear 1975 may be a pro- have glandular-plumose hairs on the adult pal-
genic isolate of agilis that arose after parthe- pi (Hunt & Cokendolpher 1991).
nogenesis had become established; males are No comparative information is available on
unknown, spermathecae are lacking. The pro- the respiratory systems of Acropsopilio spe-
genesis event may have happened at least cies, but the spiracles of A. chomulae are
twice, since the species is known from a small small and imperforate. One specimen was sac-
region of eastern North America and from Ja- rificed in order to look for tracheae, and none
pan (Shear 1996). Caddo agilis has an Oli- were found. Such a small animal with its thin
gocene fossil record (Shear 1975) from Eu- cuticle, living in a constantly humid environ-
rope, so it is less likely that the origin ofagilis ment, may be able to satisfy its respiratory
from pepperella took place via peramorpho- needs by diffusion through the body wall.
sis.
Males are known for two ofthe three South LITERATURE CITED
African species of Caddella (Shear 1975), and Bertani, R., & P.I. da Silva Junior. 2002. The first
for Hesperopilio mainae (Shear 1996). mygalomorph spider without spermathecae: Sic-
Males have been described for Austropso- kius longibulhi, with a revalidation of Sickius
piliofuscus (Hickman 1957), but for no other (Araneae, Theraphosidae, Ischnocolinae). Jour-
species of the genus; females of A. fuscus nal of Arachnology 30:519-526.
have spermathecae. Despite the highly de- Cokendolpher, J.C., & E.A. Maury. 1990. Austrop-
tailed description, Shultz and Cekalovic sopilio harvestmen (Opiliones, Cyphopalpatores,
(2003) did not mention finding spermathecae Caddidae) discovered in South America. Boletrn
in A. sudamericanus which is known only de Sociedad Biologfa Concepcion, Chile 61:59-
from females. , Goo6d2n.ight, C.J., & M.L. Goodnight. 1948. A new
Acropsopilio boopis males have never been
member of the genus Caddo (Phalangida). Jour-
collected either in North America &(Shear nal of the New York Entomological Society 56:
1975) or Japan (Suzuki 1976; Suzuki Tsu- 201-203.
rusaki 1983), and A. chilensis, widespread in Goodnight, C.J., & M.L. Goodnight. 1950. Grant
southern South America (Brazil, Chile, Ar- No. 1219 (1950), distribution and taxonomic re-
gentina), is likewise known only from females lationships of the phalangid fauna of Chiapas,
—
:
SHEAR ACROPSOP1LIO CHOMULAE FEMALE 435
Mexico. Year Book of the American Philosoph- al de Punta Lara y la ubicacfon taxonomica de
ical Society 1950:142-145. genero Acropsopilio Silvestri. Physis 23:77-81.
&
Gonzalez-Sponga, M.A. 1992. Aracnidos de Vene- Shultz, J.W. T. Cekalovic. 2003. First species of
zuela. Nueva especie del generoAcropsopilio de Austropsopilio (Opiliones, Caddoidea, Caddidae)
la Cordillera de la Costa (Caddidae). Boletfn de from South America. Journal ofArachnology 31
20-27.
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Shear, W.A. 1975. The opilionid family Caddidae
Naturales 52:43-51.
in North America, with notes on species from
Gruber, J. 1974. Bemerkungen zur Morphologic otherregions (Opiliones, Palpatores, Caddoidea).
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, Journal of Arachnology 2:65-88.
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Arachnida). Annalen Naturhistorisches Museum nus and species of harvestman from Western
in Wien 78:237-259. Australia (Opiliones: Caddidae: Acropsopilioni-
Hunt, G.S., & J.C. Cokendolpher. 1991. Ballarrinae, nae). Records ofthe Western AustralianMuseum
a new subfamily of harvestmen from the South- 17:455-460.
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Maury, E.A., R. Pinto da Rocha & J.J. Morrone. ries B, Di&vision 1 (Zoology) 26:261-273.
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127-132. 1
Ringuelet, R.A. 1962. Notas sobre Opiliones. I. Manuscript received 9 September 2003, revised 24
Acropsopilio oglobini Canals en la selva margin- November 2003.