Trichadenotecnum alexanderae, copyright Alain Hogue.

Belongs within: Psocinae.

Trichadenotecnum is a cosmopolitan genus of barklice with heavily pigmented fore wings. A Neotropical clade including T. circularoides and related species may represent the sister group to other species of the genus (Yoshizawa & Lienhard 2015).

Trichadenotecnum: six spots and spiny terminalia
Published 4 February 2013
Trichadenotecnum sexpunctatum, photographed by Brian Valentine.

The animal in the photo above is a typical representative of Trichadenotecnum, a diverse genus of the barklice. About 200 species have been assigned to this genus from almost all the major biogeographic regions of the world except Australia (Yoshizawa et al. 2007); of the two species recorded from Australia and assigned to this genus, one (Ptycta enderleini) has recently been excluded from Trichadenotecnum, and the other (Trichadenotecnum circularoides) is probably a recent introduction from the Americas (Yoshizawa & Smithers 2006). Though long regarded as suspectly heterogenous, the genus has been extensively reviewed in recent years, particularly by Kazunori Yoshizawa of Hokkaido University and associates (Yoshizawa 2001, 2004; Yoshizawa et al. 2008). Members of Trichadenotecnum are characterised by a distinctive array of wing markings, visible in the above photo. Note, in particular, the series of six submarginal spots forming a U-shape towards the end of each wing (though, confusingly, these characteristic markings can become difficult to distinguish in species in which the wings are more heavily spotted overall). The genus is also distinguished by certain features of the male terminalia (or, in layman’s terms, the bum) with a number of processes developed on the hypandrium, the posteriormost segment of the underside of the abdomen that covers the phallosome, the intromittent organ in Psocoptera. These processes vary in development between species, and often themselves bear arrays of small spines or teeth. A number of species of Trichadenotecnum also have the terminalia assymmetrically developed, with the left and right lobes of the hypandrium (for instance) differently sized and/or shaped, though the functional significance of this arrangement (if any) remains unknown.

Various views of the terminalia of Trichadenotecnum alexanderae, from Yoshizawa (2001). In life, the phallosome is contained within the underside of the terminalia.

The variability of the terminalia between species of Trichadenotecnum makes them a rich source of characters for use in taxonomy. The problem with this, of course, is that you need adult males, and that isn’t always easy. Particularly in a group like Psocoptera, which seem to show a particular tendency for parthenogenesis. A number of Trichadenotecnum species are not, as yet, known to produce males, including the aforementioned T. circularoides, necessitating identifiers to fall back largely on wing markings. Trichadenotecnum circularoides has been recorded from Angola, east Asia, Australia, North America and Brazil; the distribution of closely related species suggests that the last locality represents its original homeland with human dispersal carrying it elsewhere (Yoshizawa et al. 2008). The New World species of Trichadenotecnum appear to fall within a small number of clades: one including T. circularoides is the sister group to other members of the genus, while the T. alexanderae species group is Holarctic in distribution. The majority of New World species, however, form a single lineage referred to as the ‘bulky clade’ by Yoshizawa et al. (2008). Members of the bulky clade have a movable median tongue on the hypandrium that bears a dorsal covering of denticles or spines. Yoshizawa et al. (2008) suggested that, as the bulky clade was nested amongst a number of Old World lineages, this group may represent a relatively recent invasion of the Americas, probably by way of the Bering Strait.

Nymphs of Trichadenotecnum possess glandular hairs to which frass and pieces of lichen become attached, providing them with camouflage. This individual was photographed by Charley Eiseman.
Systematics of Trichadenotecnum

Characters (from New & Lienhard 2007, Yoshizawa & Lienhard 2015): Fore wing markings including spots in cell C; opposing spots near base of cell r; proximal band fron stigmasac passing through M+Cu fork to distal third of cell cu2; submarginal row of six spots. Male with clunial arms usually present; hypandrium usually with median tongue; apophyses present on posterior margin of hypandrium.

<==Trichadenotecnum Enderlein 1909YL15 [incl. Cryptopsocus Li 2002YL15, Trichadenopsocus Roesler 1943NL07, L02]
    |--+--+--T. bosYL15
    |  |  `--T. tambopatenseYL15
    |  `--+--T. gonzaleziYL15
    |     `--T. peruenseYL15
    `--+--+--T. corniculumYL15
       |  `--T. germinatumYL15
       |--T. marginatum groupYL15
       |    |--+--T. sabahense Yoshizawa & Lienhard 2015YL15
       |    |  `--T. sharkeyi Yoshizawa & Lienhard 2015YL15
       |    `--+--T. cynostigmus (Li 2002) [=*Cryptopsocus cynostigmus]YL15
       |       |--T. marginatum New & Thornton 1976YL15
       |       `--T. tigrinum Yoshizawa & Lienhard 2015YL15
       `--+--T. alexanderae complexM93
          |    |--T. alexanderae (Sommerman 1948)YL15, L02 [=Trichadenopsocus alexanderaeL03]
          |    |--T. castum Betz 1983YL15, M93
          |    |--T. innuptum Betz 1983M93
          |    `--T. merum Betz 1983M93
          |--T. spiniserrulum groupYL15
          |    |  i. s.: T. spiniserrulum Datta 1969L02 [=Trichadenopsocus spiniserrulusL03]
          |    |--T. ianobidensYL15
          |    `--+--T. falx Yoshizawa 2001YL15, M03
          |       `--T. furcalingumYL15
          `--+--T. ianiYL15
             |--+--T. nothoapertumYL15
             |  `--T. yamatomajus Yoshizawa 2001YL15, M03
             `--+--+--+--T. albumYL15
                |  |  `--T. incognitum Roesler 1939YL15, L98
                |  `--+--T. mixtumYL15
                |     `--+--T. latebrachiumYL15
                |        `--T. medium Thornton 1961YL15, L02 [=Loensia mediaL03, Thichorntontecnum mediumL02]
                `--+--+--T. desolatum (Chapman 1930)YL15, M93 (see below for synonymy)
                   |  `--T. tuitenseYL15
                   `--+--+--T. aconcinnumYL15
                      |  `--+--+--T. decuiYL15
                      |     |  `--T. obrienorumYL15
                      |     `--+--T. miffyYL15
                      |        `--T. slossonae (Banks 1903)YL15, M93 [=Psocus slossonaeM93; incl. T. unum Sommerman 1948M93]
                      `--+--+--T. chiapenseYL15
                         |  `--T. erwiniYL15
                         `--+--+--T. brevicornumYL15
                            |  `--T. quaesitum (Chapman 1930)YL15, M93 [=Psocus quaesitusM93]
                            `--+--T. concinnumYL15
                               `--T. nicaraguenseYL15
Trichadenotecnum incertae sedis:
  *T. sexpunctatum (Linnaeus 1758)YL15 [=Hemerobius sexpunctatusYL15, Psocus sexpunctatusL02]
  T. adika Endang, Thornton & New 2002NL07
  T. aduncatum (Li 2002) [=Trichadenopsocus aduncatus]L03
  T. alinguum Endang, Thornton & New 2002NL07
  T. alobum Endang & New 2005NL07
  T. alternatum (Li 2002) [=Trichadenopsocus alternatus]L03
  T. ampullaceum (Li 2002) [=Trichadenopsocus ampullaceus]L03
  T. angolensis Badonnel 1955B55
  T. arciforme Thornton 1961NL07
  T. baishanzuicum Li 1995L02
  T. bicolor (Li 2001) [=Trichadenopsocus bicolor]L03
  T. bidens Thornton 1961NL07 [=Loensia bidensL02]
  T. bidentatum Thornton 1984NL07 [=Trichadenopsocus bidentatusL03]
  T. bitenatum (Li 1995)L03, L02 [=Trichadenopsocus biternatus (l. c.)L03]
  T. bromoense Endang, Thornton & New 2002NL07
  T. bucciniforme Li 1993L02 [=Trichadenopsocus bucciniformisL03]
  T. calycoideum Li 2002L02
  T. cheahae Endang, Thornton & New 2002NL07
  T. chinense Li 1997L02
  T. cinnamonum Endang & New 2005NL07
  T. circulare (Hagen 1859)NL07
  T. circularoides Badonnel 1955NL07
  T. cornutum Endang & New 2005NL07
  T. dactylinum (Li 2002) [=Trichadenopsocus dactylinus]L03
  T. digitatum (Li 2002) [=Trichadenopsocus digitatus]L03
  T. diplodurum Li 2002L02
  T. emeishanense Li 2002 [=T. emeishanaense, T. emeishananse, T. emeishanse]L03
  T. felix Thornton 1961L02 [=Trichadenopsocus felixL03]
  T. galihi Endang, Thornton & New 2002NL07
  T. gallicum Lienhard 1986L98
  T. germanicum Roesler 1939L98
  T. godavarense New 1971NL07
  T. gutianum Li 1995L02
  T. hammani Endang, Thornton & New 2002NL07
  T. himalayense Li & Yang 1987L03, L02 [=Trichadenopsocus himalayaensis (l. c.)L03]
  T. imperatorium Li 1989L02
  T. imrum New & Thornton 1976NL07
  T. isocaulum Li 2002L02
  T. jaculatorum (Li 2002) [=Trichadenopsocus jaculatorus]L03
  T. jambiense Endang & New 2005NL07
  T. jinxiuense (Li 2002) [=Trichadenopsocus jinxiuensis]L03
  T. kalibiruense Endang & New 2005NL07
  T. kerinciense Endang & New 2005NL07
  T. krucilense Endang, Thornton & New 2002NL07
  T. kunmingicum Li 2002L02
  T. laticornutum Endang, Thornton & New 2002NL07
  T. mamillatum Li 2002L02
  T. maroccanum Baz 1989L98
  T. mclachlani New 1973NL07 [=Trichadenopsocus mclachlaniL03]
  T. minisexmaculatum Li & Yang 1987L03, L02 [=T. minsexmaculatum (l. c.)L03, T. minsexmaculatus (l. c.)L03]
  T. minutum Enderlein 1926NL07
  T. muaraense Endang & New 2005NL07
  T. multangulare (Li 2002) [=Trichadenopsocus multangularis]L03
  T. multicuspidatum (Li 2002) [=Trichadenopsocus multicuspidatus]L03
  T. obsitum (Enderlein 1908)L02
  T. obsubulatum Li 2002L02
  T. opiparipardale (Li 1995)L03, L02 [=Trichadenopsocus opiparipardalisL03]
  T. paradika Endang & New 2005NL07
  T. pardoides Badonnel 1955B55
  T. pardus Badonnel 1955NL07 (see below for synonymy)
  T. paululum (Li 2002) [=Trichadenopsocus paululus]L03
  T. percussum Li 2002L02
  T. pergracilum Li 2002L02
  T. periphericum (Li 2001) [=Trichadenopsocus periphericus]L03
  T. pokhariense New 1983L02
  T. proctum Endang & New 2005NL07
  T. qingshuicum Li 2002L02
  T. quadrispinosum Endang, Thornton & New 2002NL07
  T. quadruplex (Li 2002) [=Trichadenopsocus quadruplex]L03
  T. rachimi Endang & Thornton 1992NL07
  T. resupinum (Li 1997)L03, L02 [=Trichadenopsocus resupinusL03]
  T. rhomboides Li 2002L02
  T. santosai Endang & Thornton 1992NL07
  T. scoparium (Li 1995)L03, L02 [=Trichadenopsocus scopariusL03]
  T. sibolangitense Endang & New 2005NL07
  T. soekarmanni Endang, Thornton & New 2002NL07
  T. soenarti Endang, Thornton & New 2002NL07
  T. spuristipiatum Li 1997L02
  T. stipiatum Li 1992L02
  T. stipulatum (Li 2002) [=Trichadenopsocus stipulatus]L03
  T. subrotundum (Li 2002) [=Trichadenopsocus subrotundus]L03
  T. subscalare (Li 2002) [=Trichadenopsocus subscalaris]L03
  T. sufflatum Li 1993L02 [=Trichadenopsocus sufflatusL03]
  T. sumatrense Endang & New 2005NL07
  T. tenuispinum Li 1995L02
  T. thallodialum Li 2002L02
  T. trichotomum (Li 2002) [=Trichadenopsocus trichotomus]L03
  T. trigonophyllum Li 1993L02
  T. uncorne (Li 1995)L03, L02 [=Trichadenopsocus uncornisL03]
  T. uniforme (Li 2002) [=Trichadenopsocus uniformis]L03
  T. univittatum Li 2002L02
  T. vaughani Endang, Thornton & New 2002NL07
  T. waykambasense Endang & New 2005NL07
  T. waykananense Endang & New 2005NL07
  T. wuxiacum Li 1997L02
  T. xizangicum Li 2002L02
  T. majus groupNL07
    |--T. apertum Thornton 1961NL07, L02 [=Trichadenopsocus apertusL03]
    |--T. gombakense New & Lee 1992NL07
    |--T. majus (Kolbe 1880)M93 (see below for synonymy)
    `--T. malayense New 1975NL07 [=Trichadenopsocus malayaense (l. c.)L03]

Trichadenotecnum desolatum (Chapman 1930)YL15, M93 [=Psocus desolatusNL07, Trichadenotecnum (*Trichadenopsocus) desolatusM93, NL07]

Trichadenotecnum majus (Kolbe 1880)M93 [=Psocus sexpunctatus var. majorL02, T. maijum (l. c.)L03, T. majum (l. c.)L03; incl. P. major var. ocellata Enderlein 1901L02, P. major var. septentrionalis Enderlein 1910L02]

Trichadenotecnum pardus Badonnel 1955NL07 [=Trichadenopsocus pardusL03; incl. Trichadenotecnum pardidum Thornton 1961L03, Trichadenopsocus pardidusL03]

*Type species of generic name indicated


[B55] Badonnel, A. 1955. Psocoptères de l’Angola. Diamang Publicações Culturais 26: 11–267.

[L02] Li F. 2002. Psocoptera of China vol. 2. Science Press: Beijing.

[L98] Lienhard, C. 1998. Faune de France. France et Régions Limitrophes. 83. Psocoptères Euro-Méditerranéens. Fédération Française des Sociétés de Sciences Naturelles: Paris.

[L03] Lienhard, C. 2003. Nomenclatural amendments concerning Chinese Psocoptera (Insecta), with remarks on species richness. Revue Suisse de Zoologie 110 (4): 695–721.

[M93] Mockford, E. L. 1993. North American Psocoptera (Insecta). Sandhill Crane Press, Inc.

[M03] Mockford, E. L. 2003. New species and records of Psocoptera from the Kuril Islands. Mitt. Mus. Nat.kd. Berl., Dtsch. Entomol. Z. 50 (2): 191–230.

[NL07] New, T. R., & C. Lienhard. 2007. The Psocoptera of Tropical South-east Asia. Brill: Leiden.

Yoshizawa, K. 2001. A systematic revision of Japanese Trichadenotecnum Enderlein (Psocodea: ‘Psocoptera’: Psocidae: Ptyctini), with redefinition and subdivision of the genus. Invertebrate Taxonomy 15: 159–204.

Yoshizawa, K. 2004. Molecular phylogeny of major lineages of Trichadenotecnum and a review of diagnostic morphological characters (Psocoptera: Psocidae). Systematic Entomology 29: 383–394.

Yoshizawa, K., A. N. García Aldrete & E. L. Mockford. 2008. Systematics and biogeography of the New World species of Trichadenotecnum Enderlein (Insecta: Psocodea: ‘Psocoptera’: Psocidae). Zoological Journal of the Linnean Society 153: 651–723.

[YL15] Yoshizawa, K., & C. Lienhard. 2015. Synonymy of Cryptopsocus Li with Trichadenotecnum Enderlein (Insecta: Psocodea: ‘Psocoptera’: Psocidae) and description of three new species. Zootaxa 3957 (4): 480–488.

Yoshizawa, K., C. Lienhard & V. K. Thapa. 2007. Systematic study of the genus Trichadenotecnum in Nepal. Insecta Matsumurana, new series 63: 1–33.

Yoshizawa, K., & C. N. Smithers. 2006. Systematic position of Trichadenotecnum enderleini (Roesler) (Psocodea: “Psocoptera”: Psocidae). Records of the Australian Museum 58: 411–415.

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