Tiphallus torreon, Shelley & Espino & Robles, 2015

Shelley, Rowland M., Espino, Ancelmo Orona & Robles, Miguel Ángel Gallegos, 2015, A contribution on the Middle American milliped family Rhachodesmidae (Polydesmida: Leptodesmidea: Rhachodesmoidea): description of Tiphallus torreon n. sp., the first species from Coahuila, Mexico; first records from Belize; and depiction of the (super) familial distribution, Insecta Mundi 2015 (423), pp. 1-10 : 4-7

Tiphallus torreon new species

Fig. 1 , 3–6 .

Type specimens. Male holotype and one male paratype ( FSCA) collected by A. O. Espino in August 2013 along Arroyo de Palos , Sierra de Jimulco, Coahuila, Mexico ; one male and two female paratypes ( FSCA, NCSM) taken by same collector at same locality in September 2012 and 14–16 September 2011, respectively. All types were taken at the same locality, which constitutes the first definite records from Coahuila for Rhachodesmidae .

Diagnosis. Distinguished from congeneric species by the truncated, subapical acropodital projection.

Color in life ( Fig. 1 ). Dorsum and sides iridescent turquoise, lateral margins of collum and caudal paranotal corners on segments 2–18 with whitish areas varying from the tips and slight extensions along caudal margins on segments 6, 11, and 14, to large splotches covering caudal 2/3 to 3/4 of paranota on segments 5, 7, 9–10, 12–13, and 15–16. Epicranium medium turquoise, fading in interantennal and genal regions then darkening again on frons; labrum white. Pregonopodal sterna and prozonae dark to medium turquoise, fading on 7 th sternum between 9 th legs and only faintly blue thereafter. Legs 1–4 subuniformly dark turquoise, fading on legs 5–6 and only faintly blue thereafter. Hypoproct dark turquoise, paraprocts lighter.

Holotype. Length 27.6 mm, maximal width 4.6 mm, W/L ratio 16.7%. Head lightly rugulose. Epicranial suture strong, distinct, terminating in interantennal region. Genae extending laterad well beyond epicranial margins, ends narrowly rounded. Facial setae as follows: epicranial 2–2; supra-antennal 1–1; interantennal comprising two series of 1–1; subantennal 1–1; frontal comprising five series of 1–1; genal about 8–8 irregularly scattered over both surfaces; clypeal about 10–10; labral about 13–13, merging with clypeal series and continuing for about 1/3 of genal margins. Antennae reaching back to, or slightly beyond, caudal margin of 4 th tergite; 1 st antennomere subglobose, 2–6 clavate, covered with moderate vestiture beginning at midlength of 2 nd article and becoming progressively denser distad, 7 th short and truncate with four short, broad apical cones.

Metazonae lightly granular, prozonae more so; anterior margins of collum and metaterga 2–5 with short, inconspicuous, and irregularly spaced setae. Paranota flat, subplanar, extending directly laterad or angling slightly upwards/dorsad, dorsal surfaces essentially flush with those of metaterga; anterior corners rounded except for a short but distinct tooth on those of segments 3–11, teeth becoming progressively shorter, broader, and less distinct on 12 th –16 th paranota and absent thereafter; caudal corners rounded, margins subcontinuous with those of metaterga on segments 2–8, slightly emarginate on 9–16, angling progressively more caudad and becoming subacuminate on 17–19. Peritremata narrow, present on 2 nd –19 th paranota; ozopores present on segments 5, 7, 9–10, 12–13, and 15–19, located caudal to midlengths in peritrematal swellings, opening subdorsad. Epiproct moderately long, configuration subtriangular, projecting directly caudad from 19 th segment, overhanging and extending well beyond caudal paraproctal margins, apically blunt, with one long basal seta per side and four long spinneret hairs (sub)apically.

Sides of metazonae smooth to lightly granular, with only slight grooves or impressions. Strictures strong, distinct. Spiracles small, rounded, located adjacent to coxal condyles. Sternum of segment 4 with distinct, conical lobes subtending coxae of 3 rd legs; 5 th sternum with shallow central depression, 6 th strongly depressed between both leg pairs to accommodate distal halves of gonopodal telopodites. Postgonopodal sterna smooth, glabrous, with distinct bicruciform impressions on segments 8–18, caudal margins becoming progressively more concave on 7 th –16 th sterna. 1 st and 2 nd legs short, slightly crassate, with light pilosity beginning on femora; gonapophyses short, blunt, and stubby. Coxae of 3 rd legs densely pilose with moderately long, anteriorly directed lobes contacting lateral surfaces of gonopophyses when segments compressed or curled, prefemora and femora markedly less hirsute than coxae, pilosity increasing on distal articles; 4 th –7 th legs densely pilose, without structural modifications. Pregonopodal claws falcate on legs 1–2, relatively straight and curved slightly apically on 3–7. Postgonopodal podomeres densely pilose, with distoventral prefemoral trichome on legs 8–24, claws gently curved and relatively blunt. Paraprocts with strongly elevated marginal rims and long lateral setae; hypoproct smoothly semilunar with four submarginal setae.

Gonopodal aperture large, subquadrate, located entirely in metazona, compressing stricture and prozona, 1.4 mm wide and 1.8 mm long at midpoints, anterior margin flat, sides elevating progressively caudad then lowering to flat caudal margin. Gonopods in situ with coxae closely appressed together, virtually contiguous, telopodites lying subparallel to each other, overhanging anterior margin of aperture and sternum of segment 6, terminating between 6 th legs. Gonopod structure ( Fig. 3–5 ) as follows: Apodeme short; coxa small, inconspicuous, less than half as wide as telopodite, positioned directly beneath (dorsal to) latter. Prefemoral region of telopodite more than twice as wide as coxa, expanding at midlength in anterior/posterior axis then narrowing to juncture with acropodite; anterior, lateral, and caudal surfaces covered with dense vestiture; fossa large, rounded, located caudobasally and comprising>71% of medial surface, with long, flexible hairs internally along proximal, anterior, and distal margins; efferent duct/prostatic groove arising caudally from distal margin of fossa, angling anterioventrad, looping at midlength, and tapering to slender filament running along, or close to, continuation of medial prefemoral surface; latter overhanging base of acropodite, divided at midlength into two flaps, anterior overlying caudal but both flaps lying beneath loop of duct/groove. Acropodite arising at impression near telopodital midlength, medial surface terminating just beyond prefemoral flaps, lateral surface with irregular folds and grooves, anterior and caudal margins irregularly scalloped, latter with short, lightly setose, rhomboid, subapical projection proximal to two lobed terminations; inner/medial side of lateral surface with short, broad, truncated subapical projection tapering to gently curved, narrowly rounded, caudomedially directed tip.

Male paratypes. The male paratypes agree closely with the holotype in all particulars.

Female paratypes. Fragmented and unmeasurable; somatic features agreeing generally with those of holotype. Cyphopodal aperture broad, extending laterally beyond basal podomeres of 2 nd legs and encircling latter, sides and caudal margin elevated, latter with broad medial lobe extending into and constricting opening. Cyphopods tubular, oriented dorsoventrally in situ in center of opening, valvular apices slightly protruding. Valves ( Fig. 6 ) long, cupped around medial and lateral sides of oviduct opening, surfaces covered with uniformly dense vestitures, marginal hairs longer. Receptacle absent. Operculum large, located dorsolaterally, semilunar but with distomedial indentation, surface with subuniformly dense vestiture and longer marginal hairs except around indentation.

Ecology. Tiphallus torreon was found exclusively in association with rodent holes (probably excavated by the pocket gopher, Thomomys bottae ) in the high elevation forest zone between 2,400–3,000 m (7,872–9,840 ft) in the Sierra de Jimulco. It was not encountered in association with detritus or near flowing water but seems to be sensitive to rain ; more individuals emerge from the holes and stay on the surface longer with more rain. In the initial sighting, AOE, MAGR, and associates were digging in a hole when the millipeds emerged unexpectedly.

Etymology. The specific name, a noun in apposition, references the municipality containing the type locality. Its seat, Torreón (city) some 40 km (25 mi) to the north, is the center of the ninth largest metropolitan area in Mexico, which also contains communities in neighboring Durango.

Distribution ( Fig. 2 , dots). Known definitely only from the type locality (red dot) in the southwestern corner of Coahuila near the border with Durango, and we provisionally assign T. torreon to the following specimen collected ~ 128 km (80 mi) to the north-northeast (blue dot):

MEXICO: Coahuila, Sierra Las Delicias, F, 18 August 1946, R. G. Schmidt ( FMNH).

Remarks. Although the milliped looks blue in the photo ( Fig. 1 ), the pigmentation appears more on the order of turquoise under a stereomicroscope.

Figures

Figure 1. Tiphallus torreon, habitus photo showing in vivo dorsal coloration.

Figure 2. Known and projected distribution of Rhachodesmoidea. Red line, Rhachodesmidae; green star, area of Tridontomidae in Alta Verapaz Dept., Guatemala (Loomis and Hoffman 1962, Shear 1977). Red dot, type locality of Tiphallus torreon; blue dot, provisional locality in the Sierra Las Delicias. Blue triangles, rhachodesmid localities in Belize detailed in the text.

Figure 3–6. Tiphallus torreon. 3) Left gonopod of holotype, medial view. 4) Acropodite of the same, lateral view. 5) Distal acropodital extremity of the same showing the profile of the rhomboid subapical projection, subventral view. 6) Left cyphopod of female paratype, lateral view. a, acropodite; o, operculum; pf, prefemur; v, valve.