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Timema cf. californicum “ California timema (walkingstick)” Figures 79, 80 (lateral, anterior, posterior); 81, 82 (dorsal, anterior, posterior); 83, 84 (ventral, anterior, posterior) Plates 49 (lateral), 50 (dorsal), 51 (ventral) The tracheal morphology of Timema is nota- ble for the proliferation of comparatively thin tracheae that form networks throughout the body. These networks make assessment of homology difficult especially in the thorax, where differentiating similarly networked tracheae from other taxa is unclear. Identifiable homologous tracheae are labeled here, and incorporation of data from some of the 20 or so other Timema species could help to resolve ambiguous structures. Notably, T 2,3- DLT are absent in Timema, with the additional absence of the corresponding T 2,3-DB; however, the networked nature of tracheae elsewhere likely compensates for the lack of dorsal longitudinal connections. Although distantly related, the Timema thorax is rather reminiscent of termites, with (possibly) dual ventral commissures, which may be convergent. DESCRIPTION: HEAD: Head tracheae with several networked interconnections dorsoventrally; due to three-dimensional nature of head tracheal architecture, readers are encouraged to refer to models in supplementary digital data. Prominent H-DCT-VCT-Loop at anterior margin of prothorax, with smaller H-DCT and H-VCT branching from dorsal and ventral portions of loop. H-DCT extending anteriad and slightly dorsad, splitting into dorsal branch to H-DX intersection near vertex; and anteriad H-DCT-Ant branch, joining with ventral H-VCT-Ant branch and extending into H-Ant. H-DX with anteriad branches extending laterally and ventrad, reconnecting with H-VCT-Ant as H-DX-VCT-Loop. H-VCT runs anteriad, with H-VCT-Ant branching anterodorsally to join with H-DCT-Ant. H-VCT continues anteriad with H-Mx branching ven- trad; H-Mx with H-VC before branching to H-MxPlp. H-VCT with continued anterodorsal curve, with H-Md branching anteriad; H-VCT joining with H-DCT via H-VCT-Ft-Loop; H-FtLbr branching ventrad near anterior apex of H-VCT-Ft-Loop. THORAX: T 2- S with three branches: H-DCT, H-VCT, and T 2- AWL. H-DCT runs directly anteriad toward head; small T 1-Cx ventrad in middle of prothorax. H-VCT likewise running anteriad, with T 1- AL ventrad at posterior margin of prothorax; T 1- PL not present. T 1- AL with medial branch to T 1-VX. T 1-VX branching into three anteriad tracheae, extending toward head as H-VLT, with right side H-VLT fusing with H-VLT-Med anteriad of cervix. T 2- AWL runs ventrad and mediad before turning dorsally and posteriad in an S-shaped curve; small T 2-DB and T 2-VB branching dorsad and ventrally (respectively) from T 2- AWL. T 2-DB linking with apparent T 1- DLT anteriad; T 2- DLT not visible. T 2-VB runs ventrad at bottom of T 2- AWL S-curve, bifurcating into anterior and posterior branches, both leading to network of tracheae forming numerous ventral commissures. Remainder of T 2- AWL bifurcating into T 2-Wbr and T 2- AL; T 2-Wbr directly posteriad, linking with T 3- S via T 2- PWL; T 2- AL posteriad and ventrad, linking with T 2- PL and extending into midleg. T 3 with three branches: T 2- PWL, T 3- AWL, and T 3-VB. T 2- PWL runs anteriad, splitting into T 2-Wbr dorsally and T 2- PL ventrad; T 2- PL joining with T 2- AL and extending into midleg. T 3- AWL runs dorsad, curving posteriorly and splitting into T 3-Wbr posteriad and T 3- AL ventrad; T 3- AL joining with T 3- PL and extending into hind leg. T 3-VB splitting into four tracheae close to T 3- S; at least two of these extending into network of ventral commissures; several X-shaped commissure intersections present. ABDOMEN: A 1..8- S present, short A n -SB spiracular branch present on all A 1..8- S. A 1- S branching pattern slightly modified from remaining A 2..8- S, with T 3- PWL running anteriad, splitting into T 3-Wbr anteriad and T 3- PL ventrad, with T 3- PL joining with T 3- AL and extending into T 3- L. A 1..8-MLT present, with A 1..5-DB branching dorsad from A n -MLT; A 6..8-DB branching directly from A 6..8-SB. All A 1..6-DB linking with thin, sinuous A 1..6- DLT along dorsum; A n -DC not present. A 7,8- DLT substantially larger, with fanlike morphology expanding into highly tracheated hind- and midgut “appendices” (Shelomi et al., 2015). A 1..8-VB present, extending to link with sinuous A n - VLT along venter; A 2,3,6,7,8-VC present; given distribution, other A n -VC likely present but not visible. Numerous visceral tracheae, most notably forming asymmetric connectives A 4- A 5-Vi-AsymC and A 5- A 6-Vi-AsymC; A 7-Vi-VC also present., Published as part of Herhold, Hollister W, Davis, Steven R, Degrey, Samuel P & Grimaldi, David A, 2023, COMPARATIVE ANATOMY OF THE INSECT TRACHEAL SYSTEM PART 1: INTRODUCTION, APTERYGOTES, PALEOPTERA, POLYNEOPTERA, pp. 1-184 in Bulletin of the American Museum of Natural History 459 (1) on pages 1-184, DOI: 10.5531/sd.sp.55, http://zenodo.org/record/7730159, {"references":["Shelomi, M., I. R. Sitepu, K. L. Boundy-Mills, and L. S. Kimsey. 2015. Review of the gross anatomy and microbiology of the Phasmatodea digestive tract. Journal of Orthoptera Research 24 (1): 29 - 40."]}

Herhold, Hollister W, Davis, Steven R, Degrey, Samuel P, Grimaldi, David A (2023): COMPARATIVE ANATOMY OF THE INSECT TRACHEAL SYSTEM PART 1: INTRODUCTION, APTERYGOTES, PALEOPTERA, POLYNEOPTERA. Bulletin of the American Museum of Natural History 459 (1): 1-184, DOI: 10.5531/sd.sp.55, URL: http://dx.doi.org/10.5531/sd.sp.55

Barden, Phillip, Ware, Jessica L. (2017): Relevant Relicts: The Impact of Fossil Distributions on Biogeographic Reconstruction. Insect Systematics and Diversity 1 (1): 73-80, DOI: 10.1093/isd/ixx005, URL: http://dx.doi.org/10.1093/isd/ixx005

SUMMARYThe stick insect Timema chumash belongs to a sub-order of the phasmids that is thought to have diverged early from other stick insects, and which is restricted to the southwest of North America. It jumps by rapidly extending the tibiae of both its hind legs simultaneously from an initially fully flexed position, unlike any other stick insect that has been described. The hind legs are 1.5 times longer than the front and middle legs, but still represent only half the length of its body, and the femoro-tibial joints show few specialisations for jumping. In its best jumps, the wingless body is accelerated in 12 ms to a take-off velocity of 0.9 m s–1 and experiences an acceleration of 75 m s–2, the equivalent of 8 g. This performance requires an energy expenditure of 19 μJ,generates a power output of 1.6 mW and exerts a force of 3.6 mN. The jump propels the body forward a distance of 80 mm from a mean take-off angle of 39°. Heights of 20 mm were also achieved. Elevation of the jump was controlled by the initial position of the hind legs; when the hind tibiae and femora projected above the dorsal outline of the body the jump was forwards,when parallel with the long axis of the body the jump was backwards and could result in somersaulting. The jumping movements would appear to displace Timema in different directions away from a potential predator.

During early 1999 the second author made an extensive search for specimens of Timema in southern and central California. Two undescribed species were found, T. petita and T. landelsensis. New collections provided additional data on T. monikensis Vickery & Sandoval, T. boharti Tinkham, and T. knulli Strohecker. The latter is reinstated as a valid species. A third new species, T. morongensis, received from a another researcher, also is described.

Timema bartmani sp.nov. is described from San Bernardino County, California. Both sexes are known. Males show relationship with Timema podura Strohecker. Females closely resemble Timema tahoe Vickery. Timema bartmani may be the sexual ancestor of the parthenogenetic T. tahoe.

Structural features of the eggs of a basal phasmatodean, Timema monikensis Vickery & Sandoval, 1998 (Timematidae) were examined. The eggs of this species are soft and deposited coated with soil and/or other extraneous particles. The chorion, which is transparent and weakly sclerotized, is composed of an endochorion and an exochorion. The non-inclined operculum is located at the anterior pole of the egg. The chorion in the marginal region of the operculum is thinned to form an opercular collar together with the chorion of the egg body. An inverted triangular micropylar plate is on the ventral side of the egg attached to the opercular collar. The micropylar plate is without external differentiations but is specialized inside the chorion. A single micropyle, with a simple funnel-shaped chorionic opening, occurs on either side of the micropylar plate. The posterior mound, located at the posterior pole, is a thickened chorion rich in fine vertical striations, and the serosal cuticle beneath is thickened and highly specialized. The eggs of Timematidae were characterized and compared with those of Euphasmatodea and Embioptera. A phylogenetic discussion is presented, strongly supporting the assemblage of Timematodea, Euphasmatodea and Embioptera as monophyletic.

Extensive searching by Sandoval has discovered two more previously unknown species of the genus Timema, in southern California, one parthenogenetic, the other having both sexes. [