Cyphophthalmi

Aoraki inerma inerma, copyright Te Papa Tongarewa.

Belongs within: Opiliones.
Contains: Rakaia, Sironidae, Stylocellidae, Sternophthalmi.

Cyphophthalmids wait for the mountain to come to them
Published 31 August 2007
Pettalus cf. cimiciformis, from Carl Zimmer.

Pettalidae are a family of Cyphophthalmi, what are called the mite-like harvestmen. Cyphophthalmids are a fairly small group as far as is known, with probably less than fifty described species, but the number of species has been rapidly increasing in recent years. Though they are divided into about five families, cyphophthalmids are a fairly conservative bunch in appearance—the photo above is of Pettalus cf. cimiciformis* but is fairly typical of the group as a whole. They are quite distinct from other harvestmen (in fact, it is generally agreed that they are the sister-group to all others) and, rather than having the spindly build of more familiar members of the order, cyphophthalmids are minute, stocky armoured tanks. If you look closely at the picture above, you may see a light spot on either side of the body that looks a bit like an eye but it is in fact an ozophore—a raised mound bearing the opening of a stink gland. Except for members of the family Stylocellidae, cyphophthalmids have been described in the past as eyeless, but SEM studies of Pettalidae have revealed minute (often lens-less) eyes hidden on the side of the ozophore (Boyer & Giribet 2007).

*For those who aren’t already in the know, the ‘cf.’ in the name stands for the Latin confer (compare). In this case, it indicates that the animal in question is very similar to Pettalus cimiciformis, but is not definitely a member of that species.

The really interesting thing about cyphophthalmids (beyond their own intrinsic charm, of course) is their distribution patterns. Each of the various families has a definite, disjunct distribution (Boyer et al. 2007). The family Stylocellidae are restricted to south-east Asia. The Sironidae are found in what once was Laurasia—Eurasia and North America. The Neogoveidae are found in Florida, tropical South America and tropical West Africa—the tropical parts of what once was Gondwana. Two genera placed in their own families, Ogovea and Troglosiro, are found in West Africa and New Caledonia, respectively. And Pettalidae has a classic Gondwanan distribution, found in southern South America, southern Africa (including Madagascar), Sri Lanka, Australia and New Zealand.

I think I should say something here about “Gondwanan” distributions. Science has a tendency to go through fads like any other aspect of human culture. For many years, most organisms showing what we would now call a “Gondwanan” distribution were interpreted as relicts of a former world-wide distribution. As acceptance of “continental drift” and recognition of the previous existence of Gondwana increased, more and more researchers considered its potential significance for modern biogeography. Needless to say, the significance was especially apparent to workers in the southern continents, doubtless not without some aspect of asserting the importance of the all-too-often neglected Southern Hemisphere biota relative to the Northern Hemisphere. Gondwanan origins became the next big thing for everything from birds (Cracraft 2001) to beeches (Linder & Crisp 1995) to butterflies (de Jong 2003). In the last few years, the pendulum has begun to sway the other way, probably towards a more reasonable median.

The idea of a Gondwanan distribution for a given group of harvestmen particularly merits a critical look. The fossil record of harvestmen is pretty abysmal relative to the age of the group, but what record there is speaks of a remarkable degree of morphological conservatism. The Carboniferous long-legged harvestman Brigantibunum is almost indistinguishable from modern taxa (Dunlop & Anderson 2005). The cyphophthalmid Siro platypedibus Dunlop & Giribet 2003 from Bitterfeld amber (probably Oligocene or Miocene in age) is so similar to modern species that it is included in a modern genus.

In order to test whether the distribution of Pettalidae is an actual Gondwanan distribution as opposed to a relictual one, Boyer et al. (2007) tested the phylogeny of the family with just about every morphological and molecular method imaginable. They demonstrated that most of the cyphophthalmid families were monophyletic, with distribution matching phylogeny (the exception was the Laurasian Sironidae, which came out paraphyletic to the northern Gondwanan Neogoveidae and Stylocellidae).

To add another level of interest to the whole deal, most of the genera within Pettalidae each have separate geographic distributions (Boyer & Giribet 2007). Chileogovea in South America, Purcellia and Parapurcellia in southern Africa, Pettalus in Sri Lanka, Karripurcellia in Western Australia, Austropurcellia in eastern Australia. The exception is New Zealand. New Zealand has a remarkable diversity of Pettalidae, with more described species than everywhere else combined, in three genera. But let’s look a little closer. In the South Island of New Zealand, the genus Rakaia is concentrated in the east, while the genus Aoraki is found in the west from Mount Cook* north. New Zealand actually lies on the boundary between the Indo-Australian and Pacific plates, and if you were to map the distributions of the genera, you would see that Rakaia is mostly found on the Pacific plate, while Aoraki dominates on the Indo-Australian!**

*The Maori name for which just happens to be Aoraki. Not a coincidence—the genus was named after the mountain.

**I know, I said three genera. The third genus is a single species, Neopurcellia salmoni, in the southwest of the South Island.

More tales of the crunchy
Published 22 October 2008
Male of the Sri Lankan cyphophthalmid Pettalus. Photo from Gonzalo Giribet.

Sironoidea was one of the three superfamilies of Cyphophthalmi or mite-like harvestmen recognised by Shear (1980). Largely thanks to the work of Gonzalo Giribet and associates, cyphophthalmids have in recent years become the most thoroughly studied of the major groups of harvestmen. I have previously posted on them here, and I’d recommend reading through that post before this one. As originally defined by Shear, Sironoidea included two families, the Holarctic Sironidae and the temperate Gondwanan Pettalidae (the subject of the previous post). Later, Shear (1993) added the New Caledonian Troglosiro to the superfamily. Sironoidea were united by Shear (1980) on the basis of their having a single series of dorsal setae (three groups of setae in other cyphophthalmids), coxae II free from coxae III (vs. fused), and the presence of anal glands and a modified anal region. Sironoidea was the only superfamily in the infraorder Temperophthalmi, the temperate cyphophthalmids, while the other two superfamilies, Stylocelloidea (containing the single south-east Asian family Stylocellidae) and Ogoveoidea (Ogoveidae and Neogoveidae of tropical America and west Africa) in the infraorder Tropicophthalmi, both had tropical distributions. One tropical species, the Kenyan Marwe coarctata, has since been supported by Bivort & Giribet (2004) as forming a clade in the Sironidae with the genera Paramiopsalis and Iberosiro.

More recent studies have broken down Shear’s classification. Both of Shear’s infraorders are likely to be polyphyletic, but relationships between the various families are difficult to pin down. The molecular analysis of Boyer et al. (2007) identified two possible arrangements – one with Pettalidae sister to the remaining cyphophthalmids in the arrangement Sironidae + (Stylocellidae + (Troglosiro + Neogoveidae)), while the other had Stylocellidae as the basalmost branch and Pettalidae sister to the clade formed by Sironidae and (Troglosiro + Neogoveidae). In contrast, the morphological analysis of Bivort & Giribet (2004) supported a basal position for Stylocellidae with the Ogoveoidea forming a paraphyletic series to a monophyletic Sironoidea. Until recently, the belief that Stylocellidae were the only family of cyphophthalmids to retain eyes was thought to support a basal position for them, but eyes were identified in a species of Pettalidae for the first time by Sharma & Giribet (2006), and have since been shown to be widespread in the family (Boyer & Giribet, 2007). Cyphophthalmid eyes (in those species that have them) are minute, integrated into the ozophore, of doubtful functionality and lack lenses in many Pettalidae, which is how it was possible for them to have gone unnoticed.

Siro carpaticus, a cyphophthalmid species from Poland. Note that while originally described as more closely related to species now included in Siro than to species now included in Cyphophthalmus, this species has not been properly reanalysed since Boyer et al. (2005) divided the two genera, and its generic assignment is not certain. Image from here.

Even the family Sironidae, established by Shear (1980) mainly on the basis of fused anal sclerites, is not necessarily monophyletic. As with Pettalidae (see the earlier post), each of the genera recognised within Sironidae shows a distinct geographical distribution, demonstrating that vicariance has been a significant factor—in fact, the primary factor—in the diversification of these spectacularly poorly-dispersing soil animals. Interestingly, there appears to be a closer evolutionary connection for cyphophthalmids between western Europe and North America (both inhabited by members of the genus Siro) than between western Europe and eastern Europe (the latter inhabited in the Balkan peninsula by the genus Cyphophthalmus—Boyer et al. 2005), which might be regarded as a case of life imitating politics. The Iberian peninsula has been the site of a notable mini-radiation of sironids, being the only home of the monotypic genera Odontosiro lusitanicus, Paramiopsalis ramulosus and Iberosiro distylos while the genus Parasiro is found in Spain, Corsica and Italy. Other sironid genera are the Bulgarian Tranteeva paradoxa and the Japanese Suzukielus sauteri. Boyer et al. (2007) supported the monophyly of a core clade for Sironidae including Siro, Cyphophthalmus and Paramiopsalis, but Suzukielus and Parasiro were not closely associated with this clade—Suzukielus only joined the core Sironidae in the Stylocellidae-rooted tree, while Parasiro never did.

It’s worth my adding a bit more about cyphophthalmid eyes. One things arachnids are known for by the general public is their possession of multiple pairs of eyes. Harvestmen, however, stand out in this regard by never having more than a single pair of eyes (the one supposed exception, the “cyphophthalmid” Gibocellum sudeticum, seems never to have existed outside the overactive imagination of its author—Sørensen 1906). In the Phalangida (the sister clade to Cyphophthalmi containing the majority of harvestmen), the eyes are usually placed on either side of a raised structure called the ocularium or eyemound positioned on the midline of the prosoma, but there are a few examples in which the ocularium has disassociated and the eyes are positioned closer to either side of the animal. The eyes of cyphophthalmids may be homologous to the median eyes of Phalangida. Alternatively, they could correspond to the lateral eyes of other arachnids. Shultz (2007) identified the sister group of Opiliones as scorpions, which have both median and lateral eyes, so no help there. A paper in the most recent Journal of Arachnology (Alberti et al. 2008) apparently identifies the ultrastructure of cyphophthalmid eyes as more like the median eyes of other arachnids, but this paper is so new that I haven’t even seen the issue in question as yet.

Systematics of Cyphophthalmi
<==Cyphophthalmi (see below for synonymy)
    |  i. s.: Ankaratra Shear & Gruber 1996G03
    |           `--*A. franzi Shear & Gruber 1996G00
    |         Shearogovea Giribet 2011BG13
    |           `--*S. mexasca (Shear 1977) [=Neogovea mexasca]G11
    |--Pettalidae [Scopulophthalmi]GV09
    |    |  i. s.: Manangotria Shear & Gruber 1996G03
    |    |           `--*M. taolanaro Shear & Gruber 1996G00
    |    |--+--‘Purcellia’ peregrinator Lawrence 1963G03
    |    |  `--Parapurcellia Rosas Costa 1950GV09, G03
    |    |       |--*P. fissa (Lawrence 1939) [=Purcellia fissa]G00
    |    |       |--P. monticola (Lawrence 1939) [=Purcellia monticola]G00
    |    |       |--P. rumpiana (Lawrence 1933) [=Purcellia rumpiana]G00
    |    |       `--P. silvicola (Lawrence 1939) [=Purcellia silvicola]G00
    |    `--+--+--Chileogovea Roewer 1961GV09, G03
    |       |  |    |--*C. oedipus Roewer 1961G00
    |       |  |    `--C. jocasta Shear 1993G03
    |       |  `--+--Speleosiro Lawrence 1931G03
    |       |     |    `--*S. argasiformis Lawrence 1931G00
    |       |     `--Purcellia Hansen & Sørensen 1904GV09, G03
    |       |          |--*P. illustrans Hansen & Sørensen 1904G00
    |       |          `--P. transvaalica Lawrence 1963G03
    |       `--+--+--Karripurcellia Giribet 2003GV09, G03
    |          |  |    |--K. harveyi Giribet 2003G03
    |          |  |    `--+--*K. peckorum Giribet 2003G03
    |          |  |       `--K. sierwaldae Giribet 2003G03
    |          |  `--Pettalus Thorell 1876GV09, G03
    |          |       |--*P. cimiciformis (Pickard-Cambridge 1875)G07, G03 [=Cyphophthalmus cimiciformisG07]
    |          |       |--P. brevicauda Pocock 1897G03
    |          |       |--P. lampetides Sharma & Giribet 2006SG06
    |          |       `--P. thwaitesiSM08
    |          `--+--+--RakaiaGV09
    |             |  `--Neopurcellia Forster 1948GV09, G03
    |             |       `--*N. salmoni Forster 1948G00
    |             `--+--Austropurcellia Juberthie 1988GV09, G03
    |                |    |  i. s.: A. capricornia (Davies 1977) [=Neopurcellia capricornia]BG07
    |                |    |         A. woodwardi (Forster 1955) [=Rakaia woodwardi]BG07
    |                |    |--A. forsteri (Juberthie 2000)BG09, BG07 [=Neopurcellia forsteriBG07]
    |                |    `--+--A. arcticosa (Cantrell 1980)BG09, BG07 [=Rakaia arcticosaBG07]
    |                |       `--+--*A. scoparia Juberthie 1988G03, BG09, G03
    |                |          `--A. daviesae (Juberthie 1989)BG09, BG07 [=Rakaia daviesaeBG07]
    |                `--Aoraki Boyer & Giribet 2007GV09, BG07
    |                     |--+--*A. denticulata (Forster 1948)BG07, BG09, BG07 [=Rakaia denticulataBG07]
    |                     |  |    |--A. d. denticulataBG07
    |                     |  |    `--A. d. major (Forster 1948) [=Rakaia denticulata major]BG07
    |                     |  `--A. longitarsa (Forster 1952)BG09, BG07 [=Rakaia longitarsaBG07]
    |                     `--+--+--A. calcarobtusa (Forster 1952)BG09, BG07 [=Rakaia calcarobtusaBG07]
    |                        |  |    |--A. c. calcarobtusaBG07
    |                        |  |    `--A. c. westlandica (Forster 1952) [=Rakaia calcarobtusa westlandica]BG07
    |                        |  `--+--A. granulosa (Forster 1952)BG09, BG07 [=Rakaia granulosaBG07]
    |                        |     `--A. tumidata (Forster 1948)BG09, BG07 [=Rakaia tumidataBG07]
    |                        `--+--A. healyi (Forster 1948)BG09, BG07 [=Rakaia healyiBG07]
    |                           `--+--A. crypta (Forster 1948)BG09, BG07 [=Rakaia cryptaBG07]
    |                              `--A. inerma (Forster 1948)BG09, BG07 [=Rakaia inermaBG07]
    |                                   |--A. i. inermaBG07
    |                                   `--A. i. stephenensis (Forster 1952) [=Rakaia inerma stephenensis]BG07
    `--+--BoreophthalmiSG14
       |    |--SironidaeSG14
       |    `--StylocellidaeSG14
       `--SternophthalmiSG14

Cyphophthalmi [Anepignathi, Cyphophthalmidae, Cyphophthalmides, Cyphophthalmoidae, Ogoveoidea, Sironinae, Sironini, Sironoidea, Stylocellinae, Stylocellini, Temperophthalmi, Tropicophthalmi]

*Type species of generic name indicated

References

Alberti, G., E. Lipke & G. Giribet. 2008. On the ultrastructure and identity of the eyes of Cyphophthalmi based on a study of Stylocellus sp. (Opiliones, Stylocellidae). Journal of Arachnology 36 (2): 379–387.

[BG13] Benavides, L. R., & G. Giribet. 2013. A revision of selected clades of Neotropical mite harvestmen (Arachnida, Opiliones, Cyphophthalmi, Neogoveidae) with the description of eight new species. Bulletin of the Museum of Comparative Zoology 161 (1): 1–44.

Bivort, B. L. de, & G. Giribet. 2004. A new genus of cyphophthalmid from the Iberian Peninsula with a phylogenetic analysis of the Sironidae (Arachnida: Opiliones: Cyphophthalmi) and a SEM database of external morphology. Invertebrate Systematics 18: 7–52.

Boyer, S. L., R. M. Clouse, L. R. Benavides, P. Sharma, P. J. Schwendinger, I. Karunarathna & G. Giribet. 2007. Biogeography of the world: a case study from cyphophthalmid Opiliones, a globally distributed group of arachnids. Journal of Biogeography 34 (12): 2070–2085.

[BG07] Boyer, S. L., & G. Giribet. 2007. A new model Gondwanan taxon: systematics and biogeography of the harvestman family Pettalidae (Arachnida, Opiliones, Cyphophthalmi), with a taxonomic revision of genera from Australia and New Zealand. Cladistics 23 (4): 337–361.

[BG09] Boyer, S. L., & G. Giribet. 2009. Welcome back New Zealand: regional biogeography and Gondwanan origin of three endemic genera of mite harvestmen (Arachnida, Opiliones, Cyphophthalmi). Journal of Biogeography 36: 1084-1099.

Boyer, S. L., I. Karaman & G. Giribet. 2005. The genus Cyphophthalmus (Arachnida, Opiliones, Cyphophthalmi) in Europe: a phylogenetic approach to Balkan Peninsula biogeography. Molecular Phylogenetics and Evolution 36 (3): 554–567.

Cracraft, J. 2001. Avian evolution, Gondwana biogeography and the Cretaceous-Tertiary mass extinction event. Proceedings of the Royal Society of London Series B—Biological Sciences 268: 459–469.

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.

Dunlop, J. A., & G. Giribet. 2003. The first fossil cyphophthalmid (Arachnida, Opiliones) from Bitterfeld amber, Germany. Journal of Arachnology 31: 371–378.

[G00] Giribet, G. 2000. Catalogue of the Cyphophthalmi of the world (Arachnida, Opiliones). Revista Ibérica de Aracnología 2: 49–76.

[G03] Giribet, G. 2003. Karripurcellia, a new pettalid genus (Arachnida: Opiliones: Cyphophthalmi) from Western Australia, with a cladistic analysis of the family Pettalidae. Invertebrate Systematics 17: 387–406.

[G07] Giribet, G. 2007. Cyphophthalmi: historical systematic synopsis. In: Pinto-da-Rocha, R., G. Machado & G. Giribet (eds) Harvestmen: The Biology of Opiliones pp. 92–95. Harvard University Press: Cambridge (Massachusetts).

[G11] Giribet, G. 2011. Shearogovea, a new genus of Cyphophthalmi (Arachnida, Opiliones) of uncertain position of Oaxacan caves, Mexico. Breviora 528: 1–7.

[GV09] Giribet, G., L. Vogt, A. Pérez González, P. Sharma & A. B. Kury. 2009. A multilocus approach to harvestman (Arachnida: Opiliones) phylogeny with emphasis on biogeography and the systematics of Laniatores. Cladistics 25: 1–30.

Jong, R. de. 2003. Are there butterflies with Gondwanan ancestry in the Australian region? Invertebrate Systematics 17: 143–156.

Linder, H. P., & M. D. Crisp. 1995. Nothofagus and Pacific biogeography. Cladistics 11: 5–32.

[SM08] Schönhofer, A. L., & J. Martens. 2008. Revision of the genus Trogulus Latreille: the Trogulus coriziformis species-group of the western Mediterranean (Opiliones: Trogulidae). Invertebrate Systematics 22: 523–554.

[SG06] Sharma, P., & G. Giribet. 2006. A new Pettalus species (Opiliones, Cyphophthalmi, Pettalidae) from Sri Lanka with a discussion on the evolution of eyes in Cyphophthalmi. Journal of Arachnology 34 (2): 331–341.

[SG14] Sharma, P. P., & G. Giribet. 2014. A revised dated phylogeny of the arachnid order Opiliones. Frontiers in Genetics 5 (255): 1–13.

Shear, W. A. 1980. A review of the Cyphophthalmi of the United States and Mexico, with a proposed reclassification of the suborder (Arachnida, Opiliones). American Museum novitates 2705: 1–34.

Shear, W. A. 1993. The genus Troglosiro and the new family Troglosironidae (Opiliones, Cyphophthalmi). Journal of Arachnology 21: 81–90.

Shultz, J. W. 2007. A phylogenetic analysis of the arachnid orders based on morphological characters. Zoological Journal of the Linnean Society 150 (2): 221–265.

Sørensen, W. 1906. Un animal fabuleux des temps modernes. Analyse critique. Oversigt over det Konigelige Danske Videnskabernes Selskabs Forhandlinger 4: 197–232.

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