Allocapnia, PYGMAEA

Stark, Bill P. & Kondratieff, Boris C., 2012, Epiproct And Dorsal Process Structure In The Allocapnia Forbesi Frison, A. Pygmaea (Burmeister), And A. Rickeri Frison Species Groups (Plecoptera: Capniidae), And Inclusion Of A. Minima (Newport) In A New Species Group, Illiesia 8 (5), pp. 45-77 : 57

ALLOCAPNIA PYGMAEA GROUP

Ross & Ricker (1971) recognized six species ( A. aurora Ricker 1952 ; A. indianae Ricker 1952 ; A. nivicola ( Fitch 1847) ; A. ohioensis Ross & Ricker 1964 ; A. pygmaea ( Burmeister 1839) ; A. smithi Ross & Ricker 1971 ) in the A. pygmaea group. There have been no subsequent changes to this species list. In this group the apical and basal segments of the male epiproct are usually subequal in length, and at least the distal half of the apical segment is armed with a patch of wave-like spikes. On the epiproct lower limb the notch delineating the apical spoon is absent or much reduced. Abdominal terga 7-8 typically bear dorsal processes, although the 7 th tergal process may be obscure or absent (e.g. A. aurora , A. pygmaea ). The 8 th tergal process is notched and may bear a mesal tooth giving the process a trilobed appearance. Ross & Ricker placed the A. pygmaea group as the sister group to the A. rickeri group. Allocapnia pygmaea is considered the most primitive member of the complex and A. smithi and A. nivicola are considered the most derived members of the group.

The sister group hypotheses proposed by Ross & Ricker (1971) for this group were based primarily on variations of the tergal processes, and we find no suitable characters on the epiproct to suggest modifications be made to these hypotheses. Males of four species in the group ( A. indianae , A. nivicola , A. ohioensis , A. smithi ) share trilobed processes on tergum 8 ( Figs. 53 , 59 , 66 , 77 ), whereas A. aurora and A. pygmaea share bilobed processes ( Figs. 47-48 , 71- 72 ). Two of the species, A. indianae and A. ohioensis also share trilobed processes on tergum 7; this latter condition is considered by Ross & Ricker as the primitive one for tergum 7 structure “…because this [trilobed process] could have arisen as a single homeotic mutant…” and later become modified to a simpler arcuate structure in the ancestral form giving rise to A. nivicola ( Fig. 58 ) and A. smithi .

Figures

Figs. 49-54. Allocapnia indianae, Kinniconick Creek, Lewis Co., Kentucky (49-51, 54) and Grassy Creek, Carter Co., Kentucky (52-53). 49. Male terminalia, dorsal. 50. Apical segment upper limb of epiproct tip, dorsal. 51. Surface detail apical segment upper limb of epiproct, dorsal. 52. Male terminalia, lateral. 53. Abdominal tergal lobes, anterodorsal. 54. Abdominal tergal lobes, dorsal.

Figs. 55-60. Allocapnia nivicola, Tom’s Creek, Montgomery Co., Virginia. 55. Male terminalia, dorsal. 56. Apical segment upper limb of epiproct tip, dorsal. 57. Male terminalia, lateral. 58. Abdominal tergal processes, dorsal. 59. 8th tergal process, anterodorsal. 60. 8th tergal process, lateral.

Figs. 61-66. Allocapnia ohioensis, Long Branch Creek, Wayne Co., West Virginia. 61. Male terminalia, dorsal. 62. Apical segment upper limb of epiproct tip, dorsal. 63. Male terminalia, lateral. 64. Abdominal tergal processes, lateral. 65. Abdominal tergal processes, anterodorsal. 66. 8th tergal process, dorsal.

Figs. 73-78. Allocapnia smithi, Wallace Branch, Tuscaloosa Co., Alabama. 73. Male terminalia, dorsal. 74. Apical segment upper limb of epiproct tip, dorsal. 75. Surface detail apical segment upper limb of epiproct, dorsal. 76. Male terminalia, lateral. 77. 8th tergal process, dorsal. 78. 8th tergal process, lateral.

Figs. 43-48. Allocapnia aurora, Horse Creek, Greene Co., Tennessee. 43. Male terminalia, dorsal. 44. Apical segment upper limb of epiproct tip, dorsal. 45. Male terminalia, lateral. 46. 8th tergal process, lateral. 47. 8th tergal process, anterodorsal. 48. 8th tergal process, dorsal.

Figs. 67-72. Allocapnia pygmaea, Ohio River, Mason Co., West Virginia. 67. Male terminalia, dorsal. 68. Apical segment upper limb of epiproct tip, dorsal. 69. Male terminalia, lateral. 70. 8th tergal process, oblique lateral. 71. 8th tergal process, anterodorsal. 72. 8th tergal process, dorsal.