Palpatores

Acropsopilio neozelandiae, copyright Stephen Thorpe.

Belongs within: Opiliones.
Contains: Phalangiidae, Sclerosomatidae, Neopilionidae, Metopilio, Ischyropsalidoidea, Troguloidea.

The Palpatores, the long-legged harvestmen, are a diverse group of harvestmen including many of the most familiar members of the order. Members of this clade have ozopores flush with the body surface (not raised on ozophores) and simple, single claws on the legs; most (but not all) also have particularly elongate legs. Basal members of the Palpatores with small bodies and greatly enlarged eye mounds were classified until recently in a family Caddidae, but phylogenetic analyses have recently indicated that this group is para- or polyphyletic, and may represent the plesiomorphic appearance of the clade as a whole (Groh & Giribet 2015).

Remarkable things
Published 11 June 2009

Yesterday was indeed a day for remarkable things. It started when I walked into the bathroom and found a winged male embiopteran sitting on the wall above the toilet cistern. Not the usual place where one would expect to find an embiopteran. It continued when I was informed of the publication of not one but two papers of note on harvestmen.

Lateral view of the male of Neopantopsalis thaumatopoios with most of the legs removed (because there’s a limit to how much I’m willing to draw). Even for harvestmen, species of Neopantopsalis have stupidly long appendages. This figure was used in Taylor & Hunt (2009). The scale bar equals a millimetre.

The first is of note on a more personal level—my paper on the new genus Neopantopsalis has come out in Zootaxa (Taylor & Hunt 2009). This is the first of the three major papers that will be coming out of my PhD—the other two (which I’m still in the process of writing) will cover the genera Megalopsalis and Spinicrus, respectively, as well as the phylogeny of the family Monoscutidae as a whole (or, at least, as much of it as I can reliably make out—long-legged harvestmen aren’t exactly brimming over with phylogenetically useful characters). But now that the Neopantopsalis paper has completed the review process and made it into print, I can safely say that I’m not entirely happy with it. I began working on it when I found that Glenn Hunt, the last major worker on Australian harvestmen, had designated a specimen in the Queensland Museum as the type of a new species that he had unfortunately never published before he passed away (in recognition of this, I included Glenn as a second author on my manuscript). This species, it turned out, was one of a well-defined group of species found in Queensland and northern New South Wales – the group now labelled by the name Neopantopsalis. Unfortunately, distinguishing individual species within Neopantopsalis threatened to become an overwhelming task. Individual variation in almost every character was the norm rather than the exception, and in more than one case I was left at a loss to decipher whether I was dealing with a species complex or a complex species. Eventually realising that I could end up spending my entire doctorate working on this one genus (which would not be ideal), I was forced to cut my losses, pick out some well-defined exemplars that could stand in for the overall diversity, and put an appropriate manuscript together as best I could so I could move on to the next topic. So if anyone with a penchant for arachnid systematics with connections to the Queensland region is ever looking for something to do, there’s a very widespread genus there still begging to be given the attention it really requires.

The fossil remains of Mesobunus martensi, the better-preserved of the two recent finds. Figure from Huang et al. (2009).

The other paper I learnt of yesterday has perhaps got a broader appeal—the first Jurassic harvestman fossils (Huang et al. 2009). Harvestmen are purely terrestrial, not particularly vagile and mostly very delicately built. As a result, their fossil record can only be described as pitiful. There’s a couple of fossils from the Devonian, a small collection from the Carboniferous, a couple from the Cretaceous and a small smattering from the Cenozoic (mostly amber) (Dunlop 2007). However, the few fossils that we do have are quite remarkable in light of how incredibly unremarkable they are. Most fossil harvestmen are almost indistinguishable from taxa living today. Even the very oldest known harvestman, Eophalangium sheari from the Rhynie Chert, would probably fail to raise a single eyebrow if reanimated and released into the modern environent. The origin of harvestmen could not have been all that long before the time of Rhynie Chert, because it wasn’t that long before then that there wasn’t even a terrestrial environment for there to be harvestmen in. Harvestmen, it seems, are the ultimate retroactive conservatives—if it was good enough 400 million years ago, it’s good enough today.

The two new Jurassic fossils, coming from Daohuguo in China, do not buck this trend in the least. Indeed, so similar to modern long-legged harvestmen are they that Huang et al. even assign the better-preserved of the two, Mesobunus martensi, to the modern family Sclerosomatidae. They do this on the basis of “the extremely elongate legs, a single tarsal apotele [claw], a pediform [leg-like] pedipalp, and, particularly, the fusion of the first five opisthosomal tergites into a single dorsal plate”. They also note the presence of what may (or may not) be pseudoarticulations in femora of the fourth pair of legs, which (if present) would not only place Mesobunus in the Sclerosomatidae, but also within the subfamily Gagrellinae within the Sclerosomatidae. The long legs, simple claw and leg-like pedipalps are plesiomorphies for the harvestman superfamily Phalangioidea (and quite possibly for a larger subgroup of harvestmen), so are not really significant. The dorsal scute and possible pseudoarticulations are more interesting – but, unfortunately, not conclusive. A similar dorsal scute is found in other harvestmen in other suborders (such as the genus Ischyropsalis), and also (though less sclerotised) in some members of the eupnoan family Monoscutidae (notably the genus *ahem*, which however doesn’t have very long legs*). Femoral pseudoarticulations are also not unique to Sclerosomatidae—for instance, they have recently been recorded in two species of Monoscutidae by—oh, will you look at that—Taylor & Hunt (2009). So while it is true that Sclerosomatidae is the only living family that shows the exact combination of characters seen in Mesobunus, none of the characters individually is unique. Or to turn that around, while I’m not entirely convinced that Mesobunus is a sclerosomatid, I can’t exactly show that it’s not a sclerosomatid either. Unfortunately, a rock-solid identification with Sclerosomatidae would probably require examination of features such as the genitalia or spiracles – both highly unlikely to be visible in a fossil.

*I say “ahem” because it’s in press as we speak.

Reconstructions of Mesobunus from Huang et al. (in press).

If we accept for the present that Mesobunus is a sclerosomatid, that has some interesting implications for harvestman biogeography. The Phalangioidea can be roughly divided into two morphological groups, a mostly Northern Hemisphere group containing the families Phalangiidae and Sclerosomatidae, and a Southern Hemisphere group containing the families Neopilionidae and Monoscutidae*. The Phalangiidae + Sclerosomatidae group is well supported by a few good characters (most notably the structure of the spiracle) and is more than likely a good clade. The characters uniting the Southern Hemisphere families, on the other hand, are probably plesiomorphies, so this group is quite possibly paraphyletic with regard to the Northern clade (though exact relationships are currently unknown). Similar patterns, with Northern Hemisphere taxa nested among Southern Hemisphere taxa, have been observed in many groups of organisms, and it has often been suggested to indicate a Gondwanan ancestry for those groups. Birds, butterflies… there was a period when it seemed almost everything came from Gondwana. Usually, such Gondwanan ancestries were suggested to be related to the mass extinction at the end of the Cretaceous—with the Northern Hemisphere more heavily affected by the end-Cretaceous meteor impact than the South (which is entirely plausible if the Chicxulub crater in Mexico is the site of the impact), Southern Hemisphere taxa were able to radiate at the beginning of the Cenozoic and repopulate the devastated Northern Hemisphere.

*Phalangiidae extend into the Southern Hemisphere in Africa, and Sclerosomatidae in South America, but in both cases it seems likely that these are more recent invasions from Northern Hemisphere ancestors.

The problem with a Gondwanan origin for the Phalangioidea, however, is that it implies a rather recent derivation for the Northern Hemisphere clade, within the last hundred million years or so, which seems a little out of kilter with the sedate rate of harvestman evolution suggested by the fossil record (most Eocene amber fossils [including Phalangioidea], for instance, can be assigned not only to modern families but even to modern genera). On the other hand, if sclerosomatids were present in the Middle Jurassic of China as suggested by Mesobunus, then that indicates that the modern phalangioid families had diverged before Gondwana had even properly divided from the rest of Pangaea, and some other explanation is required for modern phalangioid distribution.

There’s no such thing as caddids
Published 4 July 2014
Caddo agilis, from here.

Long-time readers of this site may recall my previous rants on the subject of the prolific, but not entirely reliable, arachnologist Carl-Friedrich Roewer. Hopefully, this post will serve to rehabilitate Roewer’s image a little, because occasionally something comes along about which he was right in the first place.

Among Roewer’s innovations in Die Weberknechte der Erde, his 1923 revision of the world Opiliones fauna, was the introduction of a new family for Acropsopilio, an odd little harvestman from South America. He placed this new family in the Dyspnoi, a subgroup of the Palpatores (long-legged harvestmen) that is otherwise found in Eurasia and North America. Acropsopilio was a distinctive beast, a tiny harvestman with relatively massive eyes (just take a look at the picture below!) Over time, other authors added to the Acropsopilionidae: species are now known from Australia, New Zealand and South Africa. They are nowhere comon, though.

Acropsopilio neozelandiae, photographed by Stephen Thorpe.

In 1975, the acropsopilionids were revised by Shear (1975), who proposed that they were related to Caddo, a genus of harvestmen found in north-eastern Asian and north-eastern North America. That’s not a typo, by the way: the range of this genus includes Japan and New England, but not the spaces in between. To make things just that extra bit weirder, the genus includes two species, C. agilis and C. pepperella, both of which are found in both the sections of its overall range. Genetic analysis has demonstrated that this weirdness is real, and not just convergence or one variable species (Shultz & Regier 2009). Caddo had previously been classed as a member of the Eupnoi, the other main subgroup within the Palpatores, but resembled acropsopilionids in features such as the small size and large eyemound. Shear proposed classing them all as a single family, Caddidae, with two subfamilies: one for Caddo and one for the Acropsopilioninae. Subsequent authors have followed his lead, and the Caddidae has come to be placed within the Eupnoi as the sister taxon to the Phalangioidea (the group including the familiar long-legged harvestmen such as the field harvestman Phalangium opilio).

Nevertheless, there was still a bit of humming and hawing going on behind the scenes. Despite the overall similarities in habitus between Caddo and acropsopilionines, several of the finer details (such as the structure of the pedipalps and genitalia) were quite different. Phylogenetic studies commenting on the position of caddoids within the Opiliones had generally included Caddo only, and not included any representatives of the acropsopilionines. And so it is quite welcome to see a new publication by Groh & Giribet (in press) in which they produced a molecular phylogenetic analysis of the caddids as a whole. The result, as hinted in the first paragraph, is that the caddids are not supported as a monophyletic group. Caddo remains in its accustomed position within the Eupnoi, but the acropsopilionids are placed as the sister clade to the Dyspnoi. Roewer, it turns out, had them in the right place to begin with.

This has some interesting implications: for instance, the otherwise entirely Holarctic Dyspnoi have just acquired a Gondwanan basal group. Also, the large eyemound is either a convergent feature between Caddo and acropsopilionines, or a retained primitive feature from the palpatorean common ancestor. Groh & Giribet suggest the latter, but I suspect the former to be just as likely (it may be related to small size: some phalangioids, such as the Mediterranean Platybuninae and the Western Australian Megalopsalis tanisphyros, also have large-ish eyemounds). But the greatest surprise for yours truly was something else: one particular ‘acropsopilionine’ genus, Hesperopilio, was not placed either with Caddo or the other acropsopilionines. Instead, it was placed closer to the the phalangioid family Neopilionidae: the subject of my own research.

When I produced my revision of the Australasian phalangioid family Monoscutidae (which I ended up synonymising with Neopilionidae), I included Caddo as an outgroup taxon in my morphological phylogenetic analysis. At the time, my supervisor asked me why I didn’t include an acropsopilionine as well, but I demurred on two points. One was that, as rare as acropsopilionines were in collections, males were even rarer (there is evidence that they are commonly parthenogenetic, as for that matter is Caddo). The other was that acropsopilionine genitalia were truly bizarre, and I couldn’t determine which parts of the acropsopilionine penis corresponded to where on the monoscutid organ.

I was basing that judgment on Acropsopilio and the South African genus Caddella (offhand, there is a longstanding tradition in harvestman taxonomy that whenever the name Caddella appears in a paper, it must be mis-spelled at least once). I still stand by that judgment. But upon seeing the results of Groh and Giribet’s molecular analysis, I looked up the description of Hesperopilio (Shear 1996), which includes a drawing of the male genitalia. And suddenly, I was struck by the possibility that they could indeed be neopilionid-like. So I tried entering Hesperopilio into my original data set using the published descriptions. The result? Though missing a fair amount of data (my coding would need to be checked against actual specimens), a rough run suggests that morphology supports Hesperopilio as a neopilionid too!

The simplified version of what I end up with. Remember, this is by no means a thoroughly vetted result; this is just me going “what if I do this?”

So let that be a lesson, I suppose. Because of the belief that Hesperopilio was an acropsopilionine, I had never even considered taking a closer look at it. As it turns out, I really should have!

Harvestmen and their hairy pedipalps
Published 22 February 2016
A selection of harvestmen, showing a variety of pedipalpal morphologies, from Wolff et al. (2016). The upper two are Laniatores with spiny pedipalps; the lower two are Palpatores with leg-like pedipalps.

I’m happy to say that a new paper on which I am an author has just been made available (Wolff et al. 2016). It’s been a while (long-term unemployment has not profited my publication record, I must admit), but there are a few things still bubbling below the surface. This last entry is a study of the evolution of harvestmen’s pedipalps, the more-or-less leg-like appendages on either side of the mouth that they use for collecting, capturing and manipulating food, and particularly the sticky hairs that many harvestmen have on them. My part in this publication was fairly minimal: I provided specimens and data on Neopilionidae, and assisted with the English-language composition. Full credit goes to my co-authors, particularly our lead author Jonas Wolff who drove it all.

I’ve learnt some interesting things myself working on this paper. When I first started researching harvestmen, most of the sources I read described them as scavengers, content to get by on decaying remains that they chanced upon in their wanderings. For some harvestman species, that is indeed their chosen diet. But some other species are not content with mere leavings, preferring their meat fresh and wriggling. These species are active predators, using their pedipalps to seize springtails and other small invertebrates. As a result of their use for this and other activities, harvestmen pedipalps show a wide range of shapes and sizes: some simple and presumably multi-purpose, others strikingly modified. Many species (particularly within the Laniatores, or ‘short-legged’ harvestmen) carry long spines on the pedipalps, and one might presume these to be the more blood-thirsty harvestmen. But, as reported by Wolff et al., there are many species no less active in their hunting (if not even more so) that not only have their pedipalps unadorned with spines but have even lost or reduced the claws that usually tip the pedipalps. What is going on here?

The answer lies in these species’ possession of an alternative to spines: glandular setae. These are little hairs attached to a gland secreting a sticky glue that sits in a globule on a cluster of micro-hairs at the end of the seta, and are found in various species of the Palpatores (‘long-legged’ harvestmen). In some species the micro-hairs may be on one side, like a tooth- or a boot-brush; in others they may form a ring around the end. Using glue to capture prey can be even more effective than using spines or claws: springtails and such are often covered with scales or other loose structures that can slide off when the animal is seized, allowing the prey to escape and leaving the would-be predator with a handful of dust. Attacking the prey with multiple points of sticky glue, however, increases the chance of holding onto it, as the glue works around the scales and adheres to the body.

Two harvestmen showing convergent ‘tentacle’ pedipalps, the dyspnoan Mitostoma chrysomelas on the left and the ballarrine Ballarra longipalpis on the right, from Wolff et al. (2016).

Most harvestmen have not gone the whole hog for glandular setae; there is presumably scope for compromise with the use of the pedipalps for other purposes such as mating (the genital opening for harvestmen is around the mid-point of the underside of the body, so harvestmen mate ‘face-to-face’ and may use the pedipalps to hold onto each other). Many Palpatores possess a smattering of glandular setae at certain points on the inner side of the pedipalps only, and otherwise have a fairly underived leg-like pedipalp with a well-developed claw. One particularly interesting example that I hadn’t heard of before was the Asian species Metagagrella minax, which possesses glandular setae as a juvenile but progressively loses them as it matures. Nevertheless, there are two groups, the Dyspnoi and Ballarrinae, that possess what Wolff et al. dub the ‘tentacle’ form of pedipalp: the pedipalps are elongate with glandular setae along the entire length and lack the claw entirely. The Dyspnoi (excluding Acropsopilionidae) are a purely Northern Hemisphere lineage, whereas the Ballarrinae are restricted to the Southern Hemisphere. The two groups sit nested on opposite sides of the primary divide within Palpatores, so there is no question that the ‘tentacle’ pedipalp has evolved independently in the two groups (which is also reflected by differences in each in the relative proportions of the segments making up the pedipalp). However, there is a bit of a question about whether the ‘tentacle’ has appeared even more often: Wolff et al. assume a single origin of the Ballarrinae but this has recently been cast into doubt. This is a question that interests me directly because of something else I’ve currently got on the boil… but that’s a topic for another day.

Systematics of Palpatores
<==Palpatores [Apagosterni, Caddidae, Caddoidea, Plagiostethi]
    |--Eupnoi [Phalangioidae]GG15
    |    |  i. s.: Brigantibunum Dunlop & Anderson 2005DA05
    |    |           `--*B. listoni Dunlop & Anderson 2005DA05
    |    |         Daohugopilio Huang, Selden & Dunlop 2009HSD09
    |    |           `--*D. sheari Huang, Selden & Dunlop 2009HSD09
    |    |--PhalangioideaGS14
    |    |    |  i. s.: Oligoopilionus Ciobanu 1977C92
    |    |    |           `--*O. aquaticus Ciobanu 1977C92
    |    |    |         Petrunkevitchiana Mello-Leitão 1936C92
    |    |    |           `--*P. oculata (Petrunkevitch 1922) [=Phalangium oculatum]C92
    |    |    |         Kustarachne Scudder 1890DA05 (see below for synonymy)
    |    |    |           |--*K. tenuipes Scudder 1890KDM20
    |    |    |           |--K. conica Petrunkevitch 1913S93
    |    |    |           |--K. longipes (Petrunkevitch 1913) [=*Protopilio longipes, Nemastomoides longipes]KDM20
    |    |    |           `--K. extincta (Melander 1903)S93
    |    |    |--PhalangiidaeGS21
    |    |    `--+--SclerosomatidaeGS21
    |    |       `--+--Vibone Kauri 1961GS21, HC91
    |    |          |    `--*V. vetusta Kauri 1961HC91
    |    |          `--+--+--NeopilionidaeGS21
    |    |             |  `--Hesperopilio Shear 1996GS21, SC06
    |    |             |       |--*H. mainae Shear 1996SC06
    |    |             |       `--H. magnificus Shultz & Cekalovic 2006SC06
    |    |             `--GlobipedidaeKC20
    |    |                  |  i. s.: Diguetinus Roewer 1912KC20
    |    |                  |           `--*D. raptator Roewer 1912C92
    |    |                  |         Lanthanopilio Cokendolpher & Cokendolpher 1984KM20
    |    |                  |           `--*L. chickeringi (Roewer 1956) [=Opilio chickeringi]C92
    |    |                  |--Dalquestia Cokendolpher 1984HT12, C92
    |    |                  |    |--*D. formosa (Banks 1910)C92 [=Eurybunus formosusC92, Globipes formosusR23]
    |    |                  |    |--D. conchoCS00
    |    |                  |    |--D. grasshoffiHT12
    |    |                  |    |--D. leucopyga Cokendolpher & Sissom 2000CS00
    |    |                  |    |--D. rothorum Cokendolpher & Stockwell 1986CS00
    |    |                  |    `--D. rugosa (Schenkel 1951)E90
    |    |                  `--+--Eurybunus Banks 1893HT12, C92
    |    |                     |    |--*E. brunneus Banks 1893C92
    |    |                     |    |--E. pallidus Goodnight & Goodnight 1943GG43
    |    |                     |    |--E. riversi Goodnight & Goodnight 1943GG43
    |    |                     |    `--E. spinosus Banks 1895R23
    |    |                     `--+--MetopilioGS21
    |    |                        `--Globipes Banks 1893HT12, C92
    |    |                             |--*G. spinulatus Banks 1893C92
    |    |                             |--G. schultzeiR56
    |    |                             `--G. simplex Schenkel 1951E90
    |    `--+--Macrogyion Garwood, Dunlop et al. 2011GS14, GD11
    |       |    `--*M. cronus Garwood, Dunlop et al. 2011GD11
    |       `--Caddo Banks 1892GS14, S75 [Caddinae, Caddini, Caddoinae]
    |            |--*C. agilis Banks 1892 [incl. C. glaucopis Crosby 1904]S75
    |            |--C. dentipalpus (Koch & Berendt 1854) [=Platybunus dentipalpus]S02
    |            `--C. pepperella Shear 1975S75
    `--Dyspnoi [Nemastomini, Nemastomoidae, Trogulini]GG15
         |  i. s.: Echinopustulatus samuelnelsoni Dunlop 2004PP19
         |--+--IschyropsalidoideaGG15
         |  `--TroguloideaGG15
         `--AcropsopilionoideaK18
              |--Halitherses Giribet & Dunlop 2005 [Halithersidae]K18
              |    `--*H. grimaldii Giribet & Dunlop 2005GD05
              `--Acropsopilionidae [Acropsopilioninae, Acropsopilionoidea]GFB14
                   |--Caddella Hirst 1925 SC06 [=Cadella (l. c.)K61; incl. Oonopsopilio Lawrence 1931SC03]
                   |    |--*C. capensis Hirst 1925S75 [=C. (Oonopsopilio) capensisK61]
                   |    |--C. africana (Lawrence 1931) [=*Oonopsopilio africanus]S75
                   |    |--C. croeseri Staręga 1988S92
                   |    |--C. haddadi Lotz 2011L11
                   |    |--C. jocquei Staręga 2008L11
                   |    `--C. spatulipilis Lawrence 1934S92 (see below for synonymy)
                   |--Acropsopilio Silvestri 1904SC06 [incl. Zeopsopilio Forster 1948SC03]
                   |    |--*A. chilensis Silvestri 1904S75 (see below for synonymy)
                   |    |--A. australicus Cantrell 1980C80
                   |    |--A. boopis (Crosby 1904) [=Caddo boopis]S75
                   |    |--A. chomulae (Goodnight & Goodnight 1948) [=Caddo chomulae, A. chommulae (l. c.)]S75
                   |    |--A. neozelandiae (Forster 1948)GFB14 [=*Zeopsopilio neozelandiaeF48]
                   |    `--A. venezuelensis González-Sponga 1992GG15
                   `--Austropsopilio Forster 1955 [incl. Tasmanopilio Hickman 1957]GG15
                        |--*A. novaehollandiae Forster 1955SC03
                        |--A. altus Cantrell 1980C80
                        |--A. cygneus Hickman 1957H57
                        |--A. fuscus (Hickman 1957)GG15 [=*Tasmanopilio fuscusH57]
                        |--A. inermis Cantrell 1980C80
                        |--A. megalops (Hickman 1957) [=Tasmanopilio megalops]GG15
                        `--A. sudamericanus Shultz & Cekalovic 2003SC03
Nomen nudum: Caddo medama Suzuki 1958GG15

*Acropsopilio chilensis Silvestri 1904S75 [incl. A. normae Cekalovic 1974GG15, A. chilensis var. ogloblini Canals 1932S75]

Caddella spatulipilis Lawrence 1934S92 [=Cadella spatulipilisL34, Caddella spatulipalpis (l. c.)S75; incl. Cadella spatulipilis var. caledonica Lawrence 1934L34]

Kustarachne Scudder 1890DA05 [incl. Protopilio Petrunkevitch 1913KDM20; Kustarachnida, KustarachnidaeK13]

*Type species of generic name indicated

References

[C80] Cantrell, B. K. 1980. Additional Australian harvestmen (Arachnida: Opiliones). Journal of the Australian Entomological Society 19: 241–253.

[CS00] Cokendolpher, J. C., & W. D. Sissom. 2000. Further contributions to the study of Dalquestia (Opiliones, Sclerosomatidae). Entomological News 111 (4): 243–249.

[C92] Crawford, R. L. 1992. Catalogue of the genera and type species of the harvestman superfamily Phalangioidea (Arachnida). Burke Museum Contributions in Anthropology and Natural History 8: 1–60.

Dunlop, J. A. 2007. Paleontology. In: Pinto-da-Rocha, R., G. Machado & G. Giribet (eds) Harvestmen: The Biology of Opiliones pp. 247–265. Harvard University Press: Cambridge (Massachusetts).

[DA05] Dunlop, J. A., & L. I. Anderson. 2005. A fossil harvestman (Arachnida, Opiliones) from the Mississippian of East Kirkton, Scotland. Journal of Arachnology 33: 482–489.

[E90] Edgar, A. L. 1990. Opiliones (Phalangida). In: Dindal, D. L. (ed.) Soil Biology Guide pp. 529–581. John Wiley & Sones: New York.

[F48] Forster, R. R. 1948. A new genus and species of the family Acropsopilionidae (Opiliones) from New Zealand. Transactions of the Royal Society of New Zealand 77 (1): 139–141.

[GD11] Garwood, R. J., J. A. Dunlop, G. Giribet & M. D. Sutton. 2011. Anatomically modern Carboniferous harvestmen demonstrate early cladogenesis and stasis in Opiliones. Nature Communications 2 (444): 1–7.

[GS14] Garwood, R. J., P. P. Sharma, J. A. Dunlop & G. Giribet. 2014. A Paleozoic stem group to mite harvestmen revealed through integration of phylogenetics and development. Current Biology 24 (9): 1017–1023.

[GD05] Giribet, G., & J. A. Dunlop. 2005. First identifiable Mesozoic harvestman (Opiliones: Dyspnoi) from Cretaceous Burmese amber. Proceedings of the Royal Society of London Series B—Biological Sciences 272: 1007–1013.

[GFB14] Giribet, G., R. Fernández & S. L. Boyer. 2014. On four poorly known harvestmen from New Zealand (Arachnida: Opiliones: Cyphophthalmi: Eupnoi: Dyspnoi: Laniatores). New Zealand Journal of Zoology 41 (4): 223–233.

[GS21] Giribet, G., K. Sheridan, C. M. Baker, C. J. Painting, G. I. Holwell, P. J. Sirvid & G. Hormiga. 2021. A molecular phylogeny of the circum-Antarctic Opiliones family Neopilionidae. Invertebrate Systematics 35: 827–849.

[GG43] Goodnight, C. J., & M. L. Goodnight. 1943. New and little known phalangids from the United States. American Midland Naturalist 29 (3): 643–656.

[GG15] Groh, S., & G. Giribet. 2015. Polyphyly of Caddoidea, reinstatement of the family Acropsopilionidae in Dyspnoi, and a revised classification system of Palpatores (Arachnida, Opiliones). Cladistics 31 (3): 277–290.

[HT12] Hedin, M., N. Tsurusaki, R. Macías-Ordóñez & J. W. Shultz. 2012. Molecular systematics of sclerosomatid harvestmen (Opiliones, Phalangioidea, Sclerosomatidae): geography is better than taxonomy in predicting phylogeny. Molecular Phylogenetics and Evolution 62 (1): 224–236.

[H57] Hickman, V. V. 1957. Some Tasmanian harvestmen of the sub-order Palpatores. Papers and Proceedings of the Royal Society of Tasmania 91: 65–79.

[HSD09] Huang, D., P. A. Selden & J. A. Dunlop. 2009. Harvestmen (Arachnida: Opiliones) from the Middle Jurassic of China. Naturwissenschaften 96 (8): 955–962.

[HC91] Hunt, G. S., & J. C. Cokendolpher. 1991. Ballarrinae, a new subfamily of harvestmen from the Southern Hemisphere (Arachnida, Opiliones, Neopilionidae). Records of the Australian Museum 43: 131–169.

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