Dorsum of Erecella flava, from Roewer (1935).

Belongs within: Opiliones.
Contains: Irumuinae, Sidaminae, Assamiinae, Polycoryphinae, Dampetrinae, Trionyxellinae, Hypoxestinae, Selencinae, Metereca, Ereca, Chilon.

The Assamiidae are a family of short-legged harvestmen found in tropical and subtropical regions of the Old World. In life, the pedipalps are held crossed one over the other when at rest.

The problem with Sacesphorus
Published 10 May 2015
Probably not the subject of today’s post: an unidentified assamiid from Thailand, from here.

One of the most frustrating things about many older taxonomic resources can be the shortage of illustrations. Up until the early part of the twentieth century, at least, it was something of a rarity for a publication to include extensive figures of their subject(s). So when I was presented for my semi-random subject of the week with the Burmese assamiid Sacesphorus maculatus, described by T. Thorell in 1889, I was not entirely surprised to discover that this Asian harvestman has never actually been illustrated.

At present, Sacesphorus maculatus is the only recognised species in its genus, known only from the Bago region in southern Burma. Unfortunately, that in itself doesn’t necessarily indicate much. The Assamiidae are perhaps the most diverse group of Laniatores (short-legged harvestmen) in the tropics of the Old World, but they are also some of the least studied. The last extensive revision of the family was by our old friend Carl-Friedrich Roewer in 1935, and like many of Roewer’s classifications its accuracy is suspect. Roewer divided the assamiids between seventeen subfamilies, but the characters separating most of these subfamilies are fairly superficial and probably do not reflect actual relationships (Staręga implicitly synonymised some of the African subfamilies in 1992 when he synonymised genera from different ‘subfamilies’ together). Roewer placed Sacesphorus in the Erecinae, which he characterised by features such as the absence of a pseudonychium (a claw-like process between the two true claws at the end of each leg), smooth leg claws, a two-segmented telotarsus on the front legs, and the absence of a median spine along the front edge of the carapace. All of these are fairly generalised characters, and some (such as tarsal segment number) are probably more variable than Roewer realised. Many short-legged harvestmen possess a pseudonychium as nymphs but lose it as they grow into adulthood, and the distribution of this feature in the assamiids may require more investigation.

Similar issues attend the identification of assamiid genera. Thorell (1889) originally distinguished Sacesphorus from the genus Pygoplus, also found in Burma and eastern India, by the presence in the former of a small spine in the middle of the eyemound. Roewer recognised a number of ‘erecine’ genera in Burma and eastern India, largely on the basis of tarsal segment numbers and armature of the dorsum. The relationship between all these genera deserves a second look. Many other groups of harvestmen have been successfully raised from the Roewerian quagmire in recent years; the assamiids are still waiting.

Systematics of Assamiidae

Characters (from Santos & Prieto 2010): Prosomal shield with five processes on frontal border (central, two internal lateral and two lateral external or marginal); pedipalps not very long, tibia and tarsus dorsoventrally flattened and crossed one on another; penis with distally enlarged trunk (ventral lamina), sometimes bilobed, with variable envelope of membranes; glans cylindrical, subdistal, housing spiny or warty evaginable membrane in the shape of a funnel.

<==Assamiidae [Assamioidae, Trionyxellidae]SG11
    |--Neopygoplus Roewer 1923KP-GP19, R35
    |    |--N. jacobsoni Roewer 1923R35
    |    `--N. siamensis Suzuki 1985SG11
    `--+--+--+--Arulla parvula Suzuki 1969KP-GP19, KSP-G15
       |  |  `--Tarnus pulcherKP-GP19
       |  `--+--TrionyxellinaeKP-GP19
       |     `--+--HypoxestinaeKP-GP19
       |        `--+--PaktongiusKP-GP19
       |           `--MysoreinaeR35
       |                |--Typestus Roewer 1935R35
       |                |    `--*T. sulcatus Roewer 1935R35
       |                |--Attakattius Roewer 1929R35
       |                |    `--A. spinifrons Roewer 1929R35
       |                `--Mysorea Roewer 1935KP-GP19, R35
       |                     |--*M. brevipus Roewer 1935R35
       |                     `--M. thaiensis Suzuki 1985SG11
          `--Erecinae [Tsadseinae]SP10
               |--Valpara Roewer 1929R35
               |    `--V. albitarsis Roewer 1929R35
               |--Kukkala Roewer 1929R35
               |    `--K. trispinifrons Roewer 1929R35
               |--Mandaria Roewer 1935SP10
               |    `--*M. caeca Roewer 1935R35
               |--Merucola Roewer 1935R35
               |    `--*M. granulatus Roewer 1935 [=M. granulata]R35
               |--Dodabetta Roewer 1929R35
               |    `--D. conigera Roewer 1929R35
               |--Djemia Roewer 1935R35
               |    `--*D. cooperi Roewer 1935R35
               |--Wintonia Roewer 1923SP10
               |    `--*W. scabra Roewer 1923R35
               |--Sacesphorus Thorell 1889R35
               |    `--*S. maculatus Thorell 1889T89
               |--Parapygoplus Roewer 1912R35
               |    `--P. variatus (Thorell 1889) [=Pygoplus variatus]R35
               |--Irnia Roewer 1935R35
               |    `--*I. scabra Roewer 1935R35
               |--Bibundina Roewer 1935SP10
               |    `--*B. pectinata Roewer 1935R35
               |--Baeorix Thorell 1889R35 [=BoeorixR23]
               |    `--*B. manducus Thorell 1889T89 [=Boeorix manducusR23]
               |--Lepchana Roewer 1927R35
               |    `--L. spinipalpis Roewer 1927M77
               |--Eubaeorix Roewer 1912R35 [=Euboeorix (l. c.)R23]
               |    `--E. gravelyi Roewer 1912R35 [=Euboeorix (l. c.) gravelyiR23]
               |--Sijucavernicus Roewer 1923R35
               |    `--S. kempi Roewer 1923R35
               |--Fakoa Roewer 1923SP10
               |    `--*F. spinulata (Roewer 1915) [=Acanthophrysella spinulata]S92
               |--Buemba Roewer 1935R35
               |    `--*B. filipes Roewer 1935R35
               |--Tetecus Roewer 1935R35
               |    `--*T. tenuis Roewer 1935R35
               |--Metapygoplus Roewer 1923R35
               |    `--*M. intermedius (Loman 1892) [=Pygoplus intermedius]R35
               |--Gapotus Roewer 1935R35
               |    `--*G. frontalis Roewer 1935R35
               |--Vandarawella Roewer 1935R35
               |    `--*V. bicolor Roewer 1935R35
               |--Cereoides Roewer 1935SP10
               |    `--*C. nebulosa (Sørensen 1896) [=Cerea nebulosa]R35
               |--Cereipes Roewer 1935SP10
               |    `--*C. angusta (Roewer 1912)S92 [=Cerea angustaR35]
               |--Acanthophrysella Strand 1911R35 [=Acanthophrys Loman 1902 non Milne Edwards 1865R23]
               |    `--*A. pectinata (Loman 1902)S92 [=Acanthophrys pectinataR35]
               |--Anjolus Goodnight & Goodnight 1948GG48
               |    `--*A. malkini Goodnight & Goodnight 1948GG48
               |--Mbinia Santos & Prieto 2010SP10
               |    `--*M. xenophora Santos & Prieto 2010SP10
               |--Cardwella Roewer 1935SP10
               |    `--*C. atar (Sørensen in Henriksen 1932) [=Wintonia atar, Dampetrus atar ms]R35
               |--Ivocoryphus Lawrence 1965SP10
               |    `--*I. jezequeli Lawrence 1965S92
               |--Neocoryphus Lawrence 1965SP10
               |    `--*N. niger Lawrence 1965S92
               |--Cereodiscus Roewer 1935SP10
               |    `--*C. lesserti Roewer 1940S92
               |--Ereala Roewer 1950SP10 [incl. Faradjea Roewer 1950S92]
               |    `--*E. armata Roewer 1950 [incl. Faradjea schoutedeni Roewer 1950]S92
               |--Eregonda Roewer 1950SP10
               |    `--*E. tenuis Roewer 1950S92
               |--Termitereca Roewer 1940SP10
               |    `--*T. singularis Roewer 1940S92
               |--Angolyppa Lawrence 1957SP10
               |    `--*A. scabra Lawrence 1957S92
               |--Angopygoplus Lawrence 1951SP10
               |    `--*A. dentichelis Lawrence 1951S92
               |--Montereca Lawrence 1962L62
               |    `--*M. paucidens Lawrence 1962S92
               |--Bundukia Lawrence 1962L62
               |    `--*B. nigra Lawrence 1962S92
               |--Roewereca Lawrence 1962L62
               |    `--*R. tenebrosa Lawrence 1962S92
               |--Neobaeorix Lawrence 1962L62
               |    `--*N. cornutus Lawrence 1962 [=N. cornuta]KM20
               |--Aberdereca Goodnight & Goodnight 1959L62, S92
               |    `--*A. parva Goodnight & Goodnight 1959S92
               |--Erebalda Roewer 1940L62, S92
               |    `--*E. cryptostigma Roewer 1940S92
               |--Erecops Roewer 1940L62, S92
               |    `--*E. multispina Roewer 1940S92
               |--Kakontwea Roewer 1951L62, S92
               |    `--*K. leleupi Roewer 1951S92
               |--Lubudia Roewer 1951L62, S92
               |    `--*L. leleupi Roewer 1951S92
               |--Kasaina Lawrence 1957L62, S92
               |    `--*K. scabra Lawrence 1957S92
               |--Allereca Roewer 1961L62, S92
               |    `--*A. ruandana Roewer 1961S92
               |--Comereca Roewer 1961L62, S92
               |    `--*C. rectipes Roewer 1961S92
               |--Buniabia Roewer 1961L62, S92
               |    `--*B. filipes Roewer 1961S92
               |--Bambereca Kauri 1985K85
               |    `--*B. spinifrons Kauri 1985S92
               |--Tubereca Kauri 1985K85
               |    `--*T. biharaguana Kauri 1985S92
               |--Tundabia Roewer 1935R35
               |    |--*T. semicaeca Roewer 1935R35
               |    `--T. ugandensis Goodnight & Goodnight 1959S92
               |--Bulobana Roewer 1935R35
               |    |--*B. octopunctata Roewer 1935R35
               |    `--B. infuscata Roewer 1940S92
               |--Eupygoplus Roewer 1915R35
               |    |--E. armatus Roewer 1915R35
               |    `--E. gracilis Roewer 1927R35
               |--Cerea Sørensen 1896SP10
               |    |--*C. lugubris Sørensen 1896S92
               |    `--C. feai Roewer 1927S92 [=C. feaeR35]
               |--Izea Roewer 1927R35
               |    |--*I. pectinata Roewer 1927S92
               |    `--I. armata Roewer 1935R35
               |--Erecongoa Roewer 1950SP10
               |    |--*E. gracilis Roewer 1950S92
               |    `--E. granulata Roewer 1952S92
               |--Lygippus Roewer 1940SP10
               |    |--*L. abdominalis Roewer 1940S92
               |    `--L. machadoi Lawrence 1951S92
               |--Erecabia Roewer 1940L62, S92
               |    |--*E. hartmanni Roewer 1940S92
               |    `--E. pluridens Lawrence 1962S92
               |--Erecomma Roewer 1940L62, S92
               |    |--*E. montana Roewer 1940S92
               |    `--E. laurenti Roewer 1961S92
               |--Cereatta Staręga 1992SP10, KM20
               |    |--*C. celeripes (Loman 1910)S92 [=Cerea celeripesR35]
               |    |--C. elegans Roewer 1935R35
               |    `--C. kivuensis Roewer 1961S92
               |--Pygoplus Thorell 1889R35
               |    |--*P. obscurus Thorell 1889T89
               |    |--P. ferrugineus Thorell 1889R35
               |    `--P. trifasciatus Thorell 1889R35
               |--‘Macrobunus’ Roewer 1912 non Tullgren 1901R35
               |    |--M. aborensis Roewer 1913R35
               |    |--M. longipes Roewer 1913R35
               |    `--M. singularis Roewer 1912R35
               |--Callereca Roewer 1940SP10
               |    |--*C. gracilis Roewer 1940S92
               |    |--C. angolensis Lawrence 1949SP10
               |    `--C. teteana Roewer 1954S92
               |--Cryptopygoplus Staręga 1992R35, KM20 [incl. Lawrenciola Staręga 1992KM20]
               |    |--*C. africanus Lawrence 1931S92
               |    |--C. capriviensis Lotz 2011L11
               |    |--C. coronatus Staręga & Snegovaya 2009L11
               |    |--C. damarana (Lawrence 1931)L11 [=*Lawrenciola damaranaS92]
               |    `--C. rhodesianus (Lawrence 1931)L11 [=Lawrenciola rhodesianaR35]
               |--Propygoplus Roewer 1923R35, M77 (see below for synonymy)
               |    |--*P. maculatus (Roewer 1912) [=Parapygoplus maculatus]M77
               |    |--*Karsianga’ rugosa Roewer 1940M77
               |    |--*Sikkimula’ scabrisoma Roewer 1940M77
               |    |--P. siwalik Martens 1977M77
               |    `--*Sikkimella’ tenuipes Roewer 1927M77
               |--Lygippulus Roewer 1954L62, S92
               |    |--*L. major Roewer 1954S92
               |    |--L. nigrescens Roewer 1961S92
               |    |--L. parvulus Roewer 1954S92
               |    |--L. scaber Roewer 1954S92
               |    `--L. setipes Roewer 1961S92
               |--Erecula Roewer 1935R35
               |    |--*E. pachypes Roewer 1935R35
               |    |--E. cincta Roewer 1961S92
               |    |--E. crassipes Kauri 1985S92
               |    |--E. leleupi Lawrence 1962S92
               |    |--E. marmorata Roewer 1940S92
               |    |--E. novemdentata Roewer 1961S92
               |    `--E. septemdentata Lawrence 1957S92
               `--Erecella Staręga 1992R35, KM20
                    |--*E. lutea Roewer 1935S92
                    |--E. basilewskyi Lawrence 1962S92
                    |--E. biseriata Roewer 1961S92
                    |--E. brunnea Roewer 1940S92
                    |--E. flava Roewer 1935R35
                    |--E. nigropicta Roewer 1961S92
                    |--E. signata Roewer 1950S92
                    |--E. transversalis Roewer 1961S92
                    `--E. walikaleana Kauri 1985S92
Assamiidae incertae sedis:
  Sokodea Roewer 1935R35
    `--*S. caeca Roewer 1935R35
  Maccabeesa Roewer 1936S92
    `--*M. lawrencei Roewer 1936S92
  Aburistella Lawrence 1947S92
    `--A. flava Lawrence 1947S92
  Afroassamia Caporiacco 1940S92
    `--*A. laevipes Caporiacco 1940S92
  Bancoella Lawrence 1947S92
    `--*B. bimaculata Lawrence 1947S92
  Banconyx Lawrence 1947S92
    `--*B. dentichelis Lawrence 1947S92
  Cleoxestus Roewer 1954S92
    `--*C. luteipictus Roewer 1954S92
  Kungwea Roewer 1961S92
    `--K. scabra Roewer 1961S92
  Lukandamila Roewer 1961S92
    `--L. cookei Roewer 1961S92
  Simienatus Roewer 1956S92
    `--*S. scotti Roewer 1956S92
  Typhloburista Lawrence 1947S92
    `--*T. pusilla Lawrence 1947S92
    |--Acaca Roewer 1935R35 [incl. Pseudoacaca Caporiacco 1949S92]
    |    |--*A. albatra Roewer 1935R35
    |    `--A. liobuniformis (Caporiacco 1949) [=Pseudoacaca liobuniformis]S92
    `--Acanthacaca Roewer 1952L62, S92
         |--*A. upembensis Roewer 1952S92
         `--A. katumbea Roewer 1961S92
  Pungoica Roewer 1915K18 [incl. Pungoiella Roewer 1914S92, Pygoselenca Roewer 1953S92; Pungoicinae]
    |--*P. simoni Roewer 1914S92
    |--P. bifurcata (Roewer 1914) [=Pungoiella bifurcata; incl. Pygoselenca albisignata Roewer 1953]S92
    `--P. decorata (Koch 1839) [=Ostracidium decoratum]KM20
    |--Aburista Roewer 1935R35
    |    `--*A. termitarum Roewer 1935R35
    `--Typhlobunellus Roewer 1927R35
         |--*T. formicarum Roewer 1927S92
         `--T. platypalpis Lawrence 1947S92
    |--Drugius Roewer 1929R35
    |    `--D. parvus Roewer 1929R35
    |--Trionyxana Roewer 1927R35
    |    `--T. gracilipes Roewer 1927R35
    `--Opcochina Roewer 1927R35
         |--O. carli Roewer 1929R35
         `--O. gravelyi Roewer 1927R35
  Parazalmoxis Roewer 1913S92
    `--*P. africana Roewer 1913 (see below for synonymy)S92
  Nsorkia dorsicanaSG11
  Eupodauchenius Roewer 1912 [Eupodaucheniinae]K18
    `--*E. luteocruciatus (Loman 1910)S92 [=Selenca luteocruciataR35; incl. E. marginatus Roewer 1912S92]
  Marua Staręga 1992 [Maruinae]KM20
    |--*M. spinosa Roewer 1935S92
    `--M. schenkeli Roewer 1935R35

*Parazalmoxis africana Roewer 1913 [incl. Hypoxestus holmi Goodnight & Goodnight 1959, P. roeweri Caporiacco 1949]S92

Propygoplus Roewer 1923R35, M77 [incl. Karsianga Roewer 1940M77, Sikkimella Roewer 1927M77, Sikkimula Roewer 1940M77]

*Type species of generic name indicated


[GG48] Goodnight, C. J., & M. L. Goodnight. 1948. New phalangids from the Southwest Pacific. American Museum Novitates 1371: 1–14.

[K85] Kauri, H. 1985. Opiliones from central Africa. Koninklijk Museum voor Midden-Afrika, Turveren, België, Zoologische Wetenschappen, Annalen 245: 1–167.

[K18] Kury, A. B. 2018. Familial nomina in harvestmen (Arachnida, Opiliones). Bionomina 13: 1–27.

[KM20] Kury, A. B., A. C. Mendes, L. Cardoso, M. S. Kury & A. A. Granado. 2020. WCO-Lite: Online world catalogue of harvestmen (Arachnida, Opiliones). Version 1.0—Checklist of all valid nomina in Opiliones with authors and dates of publication up to 2018. Published by the author: Rio de Janeiro.

[KP-GP19] Kury, A. B., A. Pérez-González & D. N. Proud. 2019. A new Indo-Malayan family of Grassatores (Arachnida: Opiliones: Laniatores). Invertebrate Systematics 33: 892–906.

[KSP-G15] Kury, A. B., D. R. Souza & A. Pérez-González. 2015. World checklist of Opiliones species (Arachnida). Part 2: Laniatores—Samooidea, Zalmoxoidea and Grassatores incertae sedis. Biodiversity Data Journal 3: e6482.

[L62] Lawrence, R. F. 1962. Resultats scientifiques des missions zoologiques de l’I.R.S.A.C. en Afrique orientale (P. Basilewsky et N. Leleup, 1957). LXXIV. Opiliones. Annales du Musée Royal de l’Afrique Centrale: Sciences Zoologiques 110: 9–89.

[L11] Lotz, L. N. 2011. Three new harvestmen species from southern Africa (Arachnida: Opiliones: Caddidae, Neopilionidae, Assamiidae). Journal of Afrotropical Zoology 7: 3–8.

[M77] Martens, J. 1977. Opiliones aus dem Nepal-Himalaya. III. Oncopodidae, Phalangodidae, Assamiidae (Arachnida). Senckenbergiana Biologica 57 (4–6): 295–340.

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

[R35] Roewer, C.-F. 1935. Alte und neue Assamiidae. Weitere Weberknechte VIII. (8. Ergänzung der “Weberknechte der Erde” 1923). Veröffentlichungen aus dem Deutschen Kolonial- und Uebersee-Museum in Bremen 1: 1–168.

[SP10] Santos, R., & C. E. Prieto. 2010. Los Assamiidae (Opiliones: Assamiidae) de Río Muni (Guinea Ecuatorial), con la descripción de ocho nuevas especies. Revista de Biologia Tropical 58 (1): 203–243.

[SG11] Sharma, P. P., & G. Giribet. 2011. The evolutionary and biogeographic history of the armoured harvestmen—Laniatores phylogeny based on ten molecular markers, with the description of two new families of Opiliones (Arachnida). Invertebrate Systematics 25: 106–142.

[S92] Staręga, W. 1992. An annotated check-list of Afrotropical harvestmen, excluding the Phalangiidae (Opiliones). Annals of the Natal Museum 33 (2): 271–336.

[T89] Thorell, T. 1889. Viaggio di Leonardo Fea in Birmania e regioni vicine. XXI.—Aracnidi Artrogastri Birmani raccolti da L. Fea nel 1885–1887. Annali del Museo Civico di Storia Naturale di Genova, Serie 2a, 7: 521–729.

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