Pycnogonida

Austrodecus glaciale, copyright Claudia P. Arango.

Belongs within: Cheliceriformes.
Contains: Pantopoda.

The Pycnogonida, sea-spiders, are a group of highly distinctive marine arthropods with a tubular body bearing four to six pairs of walking legs. Feeding is via a tubular proboscis at the front of the cephalosoma, which also bears up to four pairs of appendages (the chelifores, palpi, ovigers and the first pair of walking legs) though the first three may each be absent. The upper Cambrian fossil larva Cambropycnogon klausmuelleri may represent the earliest record of Pycnogonida, sharing with crown-group sea-spiders the larval characters of massive chelicerae plus two post-cheliceral limbs not divided into podomeres, a weakly defined head shield, and mouth on a distinct forehead region (Waloszek & Dunlop 2002).

<==Pycnogonida
    |--Cambropycnogon Waloszek & Dunlop 2002 WD02
    |    `--*C. klausmuelleri Waloszek & Dunlop 2002 WD02
    `--Eupycnogonida [Palaeopycnogonida] WD02
         |--Palaeoisopus Broili 1928 SS04, B95 [Palaeoisopida, Palaeoisopodina]
         |    `--P. problematicus Broili 1928 WD02
         `--+--Austrodecus SS04
            |    |--A. glaciale SS04
            |    `--A. gordonae SS04
            |--Flagellopantopus blocki LSE13, CVR07
            `--+--Pantopoda SS04
               `--+--Palaeopantopus Broili 1928 SS04, B95 [Palaeopantopoda, Palaeopantopodina]
                  |    `--P. maucheri Broili 1929 WD02
                  `--Haliestes Siveter, Sutton et al. 2004 SS04
                       `--*H. dasos Siveter, Sutton et al. 2004 SS04

*Type species of generic name indicated

REFERENCES

[B95] Bousfield, E. L. 1995. A contribution to the natural classification of Lower and Middle Cambrian arthropods: food-gathering and feeding mechanisms. Amphipacifica 2: 3–34.

[CVR07] Charbonnier, S., J. Vannier & B. Riou. 2007. New sea spiders from the Jurassic La Voulte-sur-Rhône Lagerstätte. Proceedings of the Royal Society of London Series B—Biological Sciences 274: 2685–2691.

[LSE13] Legg, D. A., M. D. Sutton & G. D. Edgecombe. 2013. Arthropod fossil data increase congruence of morphological and molecular phylogenies. Nature Communications 4 (2485): 1–7.

[SS04] Siveter, D. J., M. D. Sutton, D. E. G. Briggs & D. J. Siveter. 2004. A Silurian sea spider. Nature 431: 978–980.

[WD02] Waloszek, D., & J. A. Dunlop. 2002. A larval sea spider (Arthropoda: Pycnogonida) from the Upper Cambrian ‘Orsten’ of Sweden, and the phylogenetic position of pycnogonids. Palaeontology 45 (3): 421–446.

Callipallenidae

Nymphon molleri, copyright Blair Patullo.

Belongs within: Pantopoda.

The Callipallenidae are a family of sea-spiders generally retaining chelifores but lacking palpi, though the phylogeny of Pycnogonida recovered by Siveter et al. (2004) placed Nymphon (which possesses both chelifores and palpi) and Pycnogonum (which lacks both) within the clade of callipallenid genera.

<==Callipallenidae MG-H11
    |--+--Pycnogonum [Pycnogonidae] SS04
    |  |    |--P. litorale (Ström 1762) (see below for synonymy) R23
    |  |    `--P. pusillum M62
    |  `--Pseudopallene SS04
    |       |--P. ambigua SS04
    |       |--P. chevron Staples 2007 MG-H11
    |       |--P. difficile Arango 2009 MG-H11
    |       `--P. watsonae Staples 2005 MG-H11
    `--+--Parapallene SS04
       |    |--P. australiensis (Hoek 1881) MG-H11
       |    |--P. challengeri Calman 1937 MG-H11
       |    |--P. famelica SS04
       |    `--P. haddoni Carpenter 1892 MG-H11
       `--+--Callipallene SS04
          |    |--C. brevirostri SS04
          |    `--C. novaezealandiae (Thompson 1884) MG-H11
          `--+--Propallene saengeri SS04
             `--Nymphon SS04
                  |  i. s.: N. gracile SS04
                  |         N. rottnesti Child 1975 MG-H11
                  |--N. surinamense SS04
                  `--+--N. micronesicum SS04
                     `--N. molleri SS04

Pycnogonum litorale (Ström 1762) [=Phalangium litorale, Pygnogonum (l. c.) litorale; incl. Ph. balaenarum Müller 1776] R23

*Type species of generic name indicated

REFERENCES

[MG-H11] McEnnulty, F. R., K. L. Gowlett-Holmes, A. Williams, F. Althaus, J. Fromont, G. C. B. Poore, T. D. O'Hara, L. Marsh, P. Kott, S. Slack-Smith, P. Alderslade & M. V. Kitahara. 2011. The deepwater megabenthic invertebrates on the western continental margin of Australia (100–1100 m depths): composition, distribution and novelty. Records of the Western Australian Museum Supplement 80: 1–191.

[M62] Monniot, F. 1962. Recherches sur les graviers a Amphioxus de la région de Banyuls-sur-Mer. Vie et Milieu 13: 231–322.

[R23] Roewer, C.-F. 1923. Die Weberknechte der Erde: Systematische Bearbeitung der bisher bekannnten Opiliones. Gustav Fischer: Jena.

[SS04] Siveter, D. J., M. D. Sutton, D. E. G. Briggs & D. J. Siveter. 2004. A Silurian sea spider. Nature 431: 978–980.

Pantopoda

Anoplodactylus evansi, copyright Claudia P. Arango.

Belongs within: Pycnogonida.
Contains: Callipallenidae.

The Pantopoda is the clade containing crown-group sea-spiders. Members of this group have the trunk reduced to a single segment; other possible synapomorphies include the absence of excretory organs, the presence of gonopore openings on the second limb podomere, cement glands in the larval chelicerae, and egg-carrying by the males (Waloszek & Dunlop 2002).

<==Pantopoda [Podosomata] WD02
    |--Colossendeidae MG-H11
    |    |--Hedgpethia calva Arango 2009 MG-H11
    |    |--Rhopalorhynchus MG-H11
    |    |    |--R. sibogae Stock 1959 MG-H11
    |    |    `--R. tenuissimum SS04
    |    |--Colossendeis RS10
    |    |    |--C. colossea Wilson 1881 MG-H11
    |    |    |--C. megalonix GV09
    |    |    |--C. melancholicus Stock 1975 S86
    |    |    `--C. stramenti GV09
    |    `--Colossopantopus Charbonnier, Vannier & Riou 2007 CVR07
    |         `--*C. boissinensis Charbonnier, Vannier & Riou 2007 CVR07
    `--Ammotheidae S86
         |  i. s.: Nymphonella Ohshima 1927 S86
         |           |--N. lambertensis Stock 1959 S86
         |           |--N. lecalvezi Guille & Soyer 1968 S86
         |           `--N. tapetis Ohshima 1927 S86
         |         Paranymphon bifilarium Arango 2009 MG-H11
         |         Palaeopycnogonides Charbonnier, Vannier & Riou 2007 CVR07
         |           `--*P. gracilis Charbonnier, Vannier & Riou 2007 CVR07
         |--Ascorhynchus Sars 1877 SS04, S86
         |    |  i. s.: A. arenicolum (Dohrn 1881) S86
         |    |         A. similis Fage 1941 S86
         |    |--A. tenuirostris SS04
         |    `--+--A. glaberrimus SS04
         |       `--A. ramipes SS04
         `--+--Eurycyde raphiaster SS04
            `--+--+--+--Cilunculus SS04
               |  |  |    |--C. armatus SS04
               |  |  |    `--C. sekiguchi SS04
               |  |  `--+--Palaeothea devonica Bergström, Stürmer & Winter 1980 SS04, WD02
               |  |     `--Ammothea hilgendorfi RS10
               |  `--+--+--Nymphopsis acinacispinata SS04
               |     |  `--Ammothella SS04
               |     |       |--A. biunguiculata SS04
               |     |       |--A. fistella SS04
               |     |       `--A. longipes M62
               |     `--+--Achelia RS10
               |        |    |--A. assimilis SS04
               |        |    |--A. australiensis SS04
               |        |    `--A. echinata Hodge 1864 GE02
               |        |--Tanystylum RS10
               |        |    |--T. haswelli SS04
               |        |    |--T. orbiculare RS10
               |        |    |--T. rehderi SS04
               |        |    `--T. zuytdorpi Arango 2009 MG-H11
               |        `--Rhynchothorax Costa 1861 SS04, S86
               |             |--R. alcicornis Krapp 1973 S86
               |             |--R. anophthalmus Arnaud 1972 S86
               |             |--R. architectus Child 1979 S86
               |             |--R. australis SS04
               |             `--R. philopsammum Hedgpeth 1951 S86
               `--+--Pallenopsis [Pallenopsidae] SS04
                     |    |--P. cidaribatus Child 1975 MG-H11
                     |    |--P. schmitti SS04
                     |    `--P. temperans Stock 1953 MG-H11
                     `--+--Callipallenidae SS04
                        `--Anoplodactylus Wilson 1878 SS04, S86
                             |  i. s.: A. anarthrus Loman 1908 S86
                             |         A. arescus S86
                             |         A. erectus GV09
                             |         A. eroticus GV09
                             |         A. pygmaeus M62
                             |         A. tarsalis Stock 1968 S86
                             |--+--A. longiceps SS04
                             |  `--Endeidae CVR07
                             |       |--Endeis RS10
                             |       |    |--E. laevis (Grube 1871) GE02
                             |       |    `--E. mollis SS04
                             |       `--Palaeoendeis Charbonnier, Vannier & Riou 2007 CVR07
                             |            `--*P. elmii Charbonnier, Vannier & Riou 2007 CVR07
                             `--+--+--A. insignis SS04
                                |  `--A. tenuicorpus SS04
                                `--+--A. glandulifer SS04
                                   `--+--A. evansi SS04
                                      `--+--A. batangensis SS04
                                         `--A. concavicollis SS04

*Type species of generic name indicated

REFERENCES

[CVR07] Charbonnier, S., J. Vannier & B. Riou. 2007. New sea spiders from the Jurassic La Voulte-sur-Rhône Lagerstätte. Proceedings of the Royal Society of London Series B—Biological Sciences 274: 2685–2691.

[GE02] Giribet, G., G. D. Edgecombe, W. C. Wheeler & C. Babbitt. 2002. Phylogeny and systematic position of Opiliones: a combined analysis of chelicerate relationships using morphological and molecular data. Cladistics 18: 5–70.

[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.

[MG-H11] McEnnulty, F. R., K. L. Gowlett-Holmes, A. Williams, F. Althaus, J. Fromont, G. C. B. Poore, T. D. O'Hara, L. Marsh, P. Kott, S. Slack-Smith, P. Alderslade & M. V. Kitahara. 2011. The deepwater megabenthic invertebrates on the western continental margin of Australia (100–1100 m depths): composition, distribution and novelty. Records of the Western Australian Museum Supplement 80: 1–191.

[M62] Monniot, F. 1962. Recherches sur les graviers a Amphioxus de la région de Banyuls-sur-Mer. Vie et Milieu 13: 231–322.

[RS10] Regier, J. C., J. W. Shultz, A. Zwick, A. Hussey, B. Ball, R. Wetzer, J. W. Martin & C. W. Cunningham. 2010. Arthropod relationships revealed by phylogenomic analysis of nuclear protein-coding sequences. Nature 463: 1079–1083.

[SS04] Siveter, D. J., M. D. Sutton, D. E. G. Briggs & D. J. Siveter. 2004. A Silurian sea spider. Nature 431: 978–980.

[S86] Stock, J. H. 1986. Pycnogonida (=Pantopoda). In: Botosaneanu, L. (ed.) Stygofauna Mundi: A Faunistic, Distributional, and Ecological Synthesis of the World Fauna inhabiting Subterranean Waters (including the Marine Interstitial) pp. 698–700. E. J. Brill/Dr. W. Backhuys: Leiden.

[WD02] Waloszek, D., & J. A. Dunlop. 2002. A larval sea spider (Arthropoda: Pycnogonida) from the Upper Cambrian ‘Orsten’ of Sweden, and the phylogenetic position of pycnogonids. Palaeontology 45 (3): 421–446.