PACHYRHAMMA
 
Pachyrhamma longipes male Kapiti Island ©Steve Trewick Pachyrhamma edwardsii group ©Steve Trewick P. edwardsii male

Pachyrhamma has recently been revised and now includes Gymnoplectron and Turbottoplectron (with the possible exception of Turbottoplectron unicolor Salmon- Three Kings Islands) (see Cook et al. 2010).

Species of Pachyrhamma Brunner v. Wattenwyl, 1888 are large as adults, often spanning 15 cm. Pachyrhamma are the most recognised of New Zealand tokoriro or cave weta as several species regularly inhabit caves, tunnels and long-drops. However, many species are either only rarely found in these situations or never. For instance P. longipes, which is most readily recognised by the large linear spines on the hind tibiae is found in cavities in trees, whereas P. edwardsii is found in all sorts of large, dark spaces (trees, caves, tunnels etc). Some cave dwelling species (e.g. P. waitomoense in the Waitomo area, Waikato) have localised ranges, whereas others (again P. edwardsii) have broad spatial range.

Numerous species names are recorded as associated with this genus but some are likely to be synonyms, and some have not been encountered since they were described and might be considered dubious.

Pachyrhamma edwardsii (Scudder, 1869)
Adults are pale beige with prominent dark nearly black bands across posterior margins of thoracic and admoninal segments so they look striped. This species is most frequently found in caves and similar large cavities but also occurs throughout bush. Some populations are now isolated in cave entrances surrounded by modified pasture habitat.
Body length: Up to 41mm. Av. 35mm.      
Ovipositor: 0.875 x body length = 30.6mm.
Antennae: 4.5 -5 x body length = 157 – 175mm.
Leg: body ratio
Fore:    2:1=70mm.
Mid:     1.9:1=66.5mm.
Hind:    3.17:1 = 111mm
Locality: Waikato, Hawke’s Bay, Wairarapa, Horowhenua, Wellington, Marlborough, Abel Tasman National Park. Note, this species has many earlier synonymy’s.

Pachyrhamma acanthocera (Milligan, 1926)
Antennae of adult males bears several large blunt or hooked spines.
Body length:  23mm. Antennae:      183mm.
Legs:  Femur     Tibia        Tarsus       total
Fore:   25mm     26mm        17mm      68mm Mid:    23mm     26mm        16mm      65mm. Hind:   51mm    62mm        24mm      137mm
Locality: Waitakere Ranges and vicinity of Auckland Notes:

Pachyrhamma spinosum (Richards, 1961)
Nearly uniform beige body colour with paler cream posterior margin to segments.
Body length:  Up to 29mm. Av.27mm     Ovipositor: sub equal with body (27mm.) Antennae: 7 x body length = 189mm. Male has 3 or 4 short, blunt dorsal spines in the middle portion, 1 short, sharply pointed near proximal end.
Leg: body ratio           
                    Male                                  Female
Fore:    2.2:1    = 59.4mm.           1.8:1    = 48.6mm
Mid:     2.1:1    = 56.7mm.           1.7:1    = 45.9mm.
Hind:   4.4:1    = 118.8mm           3.2:1    = 86.4mm
Locality: In Rimu-Tawa forest, Te Pu, Rotorua

Pachyrhamma uncatum Richards, 1959 and Pachyrhamma fuscum Richards, 1959, were described together from specimens collected in gold mine tunnels in the Thames area. Among the specimens two male forms are apparent, one having blunt spines on the antennae (P. fusca) similar to P. acanthocera, and one not (P. uncata).
Body length: Male: 26mm, female 23mm.
Leg: body ratio                 
            Male          Female
Fore:     2.1-2.3: 1   1.8-2.1: 1  
Mid:      2.1-2.3: 1    1.8-1.9: 1  
Hind:    4.5-5: 1       3.3-3.6: 1  
Locality: Gold-mining tunnels, Thames.

Pachyrhamma waitomoense Richards, 1958
Body length: Male: Av = 32mm     Female: Av = 30mm  
Ovipositor: = 32mm
Antennae: Male, 5.5-6 x body length =176-192mm Female, 4.8- 5.3 x body length =144-159mm. No spines present on flagellum of either male or female.
Leg: body ratio                   
                Male                          Female
Fore:     1.9: 1 = 1.9x32=60.8mm     1.8: 1 = 1.8x30 = 54mm
Mid:         2: 1 =  2x32=64mm          1.7: 1 = 1.7x30 = 51mm
Hind:     4.6: 1 = 4.6x32=147.2mm  3.3: 1 = 3.3x30 = 99mm
Locality: Waitomo caves, Ruakuri Reserve north of Te Kuiti.

Pachyrhamma waipuense Richards, 1960
Body length:  Male: up to 30mm. Av. 27mm. Female: up to 28mm. Av. 25mm. 
Ovipositor:  25mm Antennae: 9 x body length = 243mm.    6 x body length = 150mm.      “Middle portion of flagellum in male armed with a number of short, blunt dorsal spines.” Leg: body ratio                           
                Male                         Female
Fore:  2.9:1   = 78.3       2:1    =      50mm.
Mid:    2.8:1   = 75.6      1.9:1  =      47.5mm.
Hind:  5.9:1   = 159.3     3.6:1  =      90mm.
Locality: Limestone Caves, Waipu


Pachyrhamma longipes (Colenso, 1887)
A very large species with nearly uniform dark brown colouration. Hind tibiae are each armed with two rows of prominent linear spines, so they are spiney like blackberry stems. Encountered in hollow trees or after emerging at night, but probably under recorded.
Body length:  Up to 41mm. Av. 32.1mm.               
Ovipositor:30mm
Antennae: 4.2 x body length = up to 172mm.  Av.135mm.
Leg: body ratio                      
Male                                       Female
Fore:   2.19:1 =     67.4mm.         1.72:1  =    55.2mm.
Mid:    2.28:1 =     73.4mm.         1.62:1  =    52mm.
Hind:  4.52:1 =     145mm.           3.0:1   =    96.3mm
Locality: Norsewood, Waipawa on Totara trees, Coromandel, near Auckland, Kaitoke, Urawera, Taumarunui, Mt Taranaki, Wairongomai Featherston, Akatarawa, Days Bay Bush, Waitaanga Nth Taranaki, Wainuiomata, Waitomo in bush, Nth Auckland.
Note: Richards (1959) described Pachyrhamma longicauda as similar to Pachyrhamma longipes (Colenso), but P. longicauda may be a synonym for P. longipes.

Pachyrhamma giganteum (Richards, 1962)
Body length: Male:  48mm.    Female: 42mm.  
Ovipositor: 0.8 x body length = 33.6mm Antennae: “Male has a short, pointed, prolateral spine on antennae. Absent in female.”   Leg: body ratio                                
           Male                           Female
Fore:     1.6:1    = 76.8mm.    1.6:1      = 67.2mm.
Mid:      1.6:1    = 76.8mm.    1.5:1      = 63mm.
Hind:     3.2:1     = 153.6       2.7:1      = 113.4mm
Locality:  In cave, Tawhiti Rahi Island. Poor Knights group Notes: "G. giganteum" is most similar to "G. spinosa" (Richards 1962) but differs in: the greater number of lineal spines on fore, mid and hind femora, the shape of the sub genital plate in the female, the presence of a postero-median tubercule on the suranal plate of the female, much greater in size.

Pachyrhamma (Turbottoplectron) unicolor (Salmon, 1948)
Body length:  Up to 2.5cm  
Ovipositor: No data from Salmon. Antennae: “very long, towards apex antennae become heavily clothed with fine hairs which are approximately as long as the diameter of the segments” no measurements given by Salmon.
Legs:   Salmon provides leg spination details but no leg lengths.
Locality: Great Island, Three Kings Islands.
Notes: The defining characteristic used by Salmon appears to be “A uniform dark chestnut brown (colour) on the body and appendages; base of hind femora with a number of transverse ocheous [sic] stripes.” Described from a male only.

Pachyrhamma delli (Richards, 1954)
Body length:    Male:   26mm.    Female:    31mm.
Ovipositor: 0.8 x body length = 26mm. Antennae: 3.5-4 x body length = 91-104mm     109-124mm.
Leg: body ratio                 
            Male                          Female
Fore:              1.9: 1   = 49.4mm.           1.6: 1   = 49.6mm.
Mid:               1.9: 1   = 49.4mm.           1.6: 1   = 49.6mm.
Hind:             3.24: 1   = 84.5mm.         2.7: 1   = 84mm.
Locality: Stillwater River Base Camp, Carswell Sound, Fiordland, under a log and in rotten tree trunk. Lake Te Au, near the South Arm of Lake Te Anau, in rotten log.
Notes: Formerly known as Macropathus delli. "Male Suranal plate; central dorsal surface bearing a very large, blunt spine, thickly clothed with short golden setae.”

Pachyrhamma tuarti (Richards, 1961)
Body length: Up to 29mm. Av. 27mm.  Ovipositor: 0.8 x body length = 22.4mm. Antennae:  “Sexual dimorphism poorly developed antennae of male slightly stouter and longer than female. No spines present on flagellum of male or female” (No measurement data provided by Richards)
Leg: body ratio                   
             Male                                  Female
Fore:      1.6:1    = 44.8mm.     1.5:1       = 42mm.
Mid:       1.6:1    = 44.8mm.     1.5:1       = 42mm.
Hind:     3.1:1    = 86.8mm.      2.7:1      = 75.6mm
Locality:  Otahuia Canyon, Rotorua. In Rimu-Tawa forest Te Pu, Rotorua.

Pachyrhamma ngongatahaense (Richards, 1961)
Body length: Male:  up to 30mm. Female: up to 24mm. Ovipositor: 0.8 x body length = 19.2mm. Antennae:  Richards does not state length merely; “sexual dimorphism poorly developed, antennae of male slightly stouter and longer than those of female, no spines present on flagellum of male or female.”
Leg: body ratio              
             Male                   Female
Fore:    1.5:1   = 45mm.           1.4:1    = 33.6mm.
Mid:     1.5:1   = 45mm.           1.5:1    = 36 mm.
Hind:   3.1:1   = 84.5mm         2.6:1    = 62.4mm.
Locality: Government Game Farm, Ngongataha, Rotorua.

References:

  • Cook LD, Trewick SA, Morgan-Richards M, Johns PM. 2010. Status of the New Zealand cave weta (Rhaphidophoridae) genera Pachyrhamma, Gymnoplectron and Turbottoplectron. Invertebrate Systematics 24: 131-138.
  • Hutton F.W. 1897 The Stenopelmatidae of New Zealand. Transactions and Proceedings of the New Zealand Institute 29: 208-242
  • Hutton F.W. 1899 Supplement to the Stenopelmatidae of New Zealand. Transactions and Proceedings of the New Zealand Institute 31: 40-43.
  • Milligan D.D. 1926. The genus Pachyrhamma (Rhaphidophorinae: Orthoptera). A new species from New Zealand. Transactions of the Royal Society of New Zealand 56: 79–80.
  • Richards, A.M. 1954. The systematics and ecology of the genus Macropathus Walker, 1869 (Orthoptera, Rhaphidophoridae). Transactions of the Royal Society of New Zealand 82: 739–762
  • Richards, A.M. 1961. Revision of the Rhaphidophoridae (Orthoptera) of New Zealand. Part IX. The genus Gymnoplectron Hutton, 1897. Transactions of the Royal Society of New Zealand 1: 323–327.
  • Scudder S.H. 1869. A new cave insect from New Zealand. Proceedings of the Boston Society of Natural History 12: 408–409.