Pseudojulus mississippiensis, Shelley, Rowland M., 2007

Shelley, Rowland M., 2007, Rediagnoses of the milliped genera Pseudojulus Bollman, 1887, and Arvechambus Causey, 1963, in the southeastern USA; description of P. mississippiensis, n. sp. and proposal of the subtribe Pseudojulina (Julida: Parajulidae: Parajulinae: Aniulini), Zootaxa 1541, pp. 1-16 : 5-8

Pseudojulus mississippiensis , new species

Figs. 2–10

Type specimens. ɗ holotype and 2Ψ paratypes ( NCSM) collected by M. & J. MacGown, 4–11 September 1991, along on state hwy. 7 near LeFlore & ca. 13 mi (20.8 km) SW Grenada (T21N, R2E, sec.12, 13N, & R3E, sec.7S, 18N), Grenada Co., Mississippi.

Diagnosis. A large-bodied species characterized by fusion of the ag coxal lobes and posterior syncoxal processes; pg telopodite in form of sigmoid curve, essentially subequal in breadth throughout length, without noticeable subapical lobe, prefemoral process slender, lying caudal to telopodite and essentially subequal in length to latter. Cyphopodal gynaspis large, lobes deeply divided, expanding caudad into second, parallel & subequivalent piece.

Coloration. Color in life unknown. Pleuroterga substantially faded after 15 years in preservative, collum and pleurotergites 2–5 faintly reticulated, midbody pleurotergites apparently banded with different shades of brown. Epicranium mottled light brown caudal to midlength, uniformly brown thereafter with color fading on frons. Epiproct & paraprocts brown anteriad, fading caudad. Antennae becoming progressively darker through 6th antennomere, ultimate article lighter.

Holotype. Body relatively long and moderately-broad, parallel-sided; ca. 61 rings including epiproct, last 2 rings legless; length ca. 41.5 mm, maximum width 2.7 mm.

Head smooth, polished; epicranium punctate, vertigial groove terminating in supra-antennal region. Ocellaria forming inverted triangle, with ca. 56 ocelli arranged in 8 sublinear rows: 9, 10, 9, 8, 7, 6, 5, 2. Epicranial setae 1-1, clypeal 2-2, labral about 9-9. Antennae reaching back to midlength of 3rd pleurotergite, becoming progressively more setose distad, 1st antennomere subglobose, 2–6 strongly clavate, 7 short and truncate with 4 conical sensory cones, no other sensory structures apparent; relative lengths of antennomeres 2>3>4>5>6>1>7. Ventrolateral corner of mandibular stipes (Fig. 2) prolonged into broad, apically rounded lobe.

FIGURES 2–5. Pseudojulus mississippiensis , somatic features of holotype. 2, mandibular stipes, lateral view. 3, distal podomeres of right 1st leg, submedial view. 4, penial apparatus, lateral view of right side. 5, the same, dorsal view. Scale line = 1.67 mm for figs. 2 & 4, 1.00 mm for figs. 3 & 5.

Dorsum smooth and glossy, glabrous except for a pair of parallel-sided paramedian setae arising from caudal margins of collum and 2nd pleurotergite. Collum enlarged, slightly overlapping epicranium, lateral margins sublinear. Pleurotergites virtually identical excepting shorter ones at caudal extremity and 6th & 7th, which are substantially swollen. Ventrolateral striae strong and conspicuous through pleurotergite 7, becoming fainter thereafter and inconspicuous around pleurotergite 14. Defensive glands arising on pleurotergite 6, continuing through 58. Epiproct long and spiniform, overhanging and extending well beyond caudal extremities of paraprocts; latter with margins strongly thickened and 3 moderately long setae arising anterior to rims; hypoproct sublunar, with a pair of subapical and basal setae.

1st legs (Fig. 3) with 6 lightly hirsute podomeres, strongly enlarged and crassate, curving gently anteriomediad and overhanging frontal region of head, relative lengths of podomeres 5=6>4>2>3>1; tibiae substantially broader than other podomeres, with "sphaerotrichomes" on anterior surfaces, tarsi basally broad, narrowing slightly distad, claws short, apically blunt, directed anteriomediad. 2nd legs short and narrow, becoming progressively more hirsute distad, directed ventrad and incorporated into penial apparatus, with 4 articles and minute claw, margins of ultimate article irregularly indented into "pseudoarticles." Subsequent legs subsimilar, with 6 articles, becoming progressively more setose distad, claws gently curved, shorter than & obscured by overlying hairs of ultimate podomere, apically acuminate. Penial apparatus (Figs. 4–5) bilobed, curving gently anteriad, divided for entire length but lobes overlapping and closely appressed to each other, with a short, apically divided projection arising from dorsal surface ("beneath" penial apparatus), extending caudad to level of 4th sternum (between 3rd legs).

Sternum of 8th pleurotergite destroyed during gonopod dissection. Anterior gonopods ( Figs. 6–8 ) with short, broad, shallowly bilobed sternum (S) situated dorsal to prominent anterior coxal lobes (ACL); latter joined along gonopodal midline, fused basally but segregated distad, lateral margins angular, extending ventrad to level of midlength of telopodite (AT); latter short, rounded, and strongly clavate, with two distinct lateral lobes; lateral syncoxal process (LSP) broad, curving strongly anteriad and narrowing to acuminate tip, with small subterminal lobe on outer/ventral margin; posterior syncoxal lobes (PSL) subsimilar to, but smaller than, anterior coxal lobes, fused for nearly entire lengths along gonopodal midline, shallowly indented apically. Posterior gonopod telopodite ( Fig. 9 , PT) moderately broad, essentially of subequal breadth throughout length, narrowing only apically to bilobed tip, in form of elongated sigmoid curve; prefemoral process (PFP) arising basally on medial side of prefemur, extending directly ventrad for 2/3 of length and positioned caudal to telopodite, curving broadly anteriad and narrowing to narrowly rounded tip, nearly as long as telopodite; prostatic groove running along medial surface of telopodite, opening in slight apical impression.

Female paratype. Length 51.1 mm, maximum width 3.0 mm, 63 rings including epiproct, last two rings legless. Agreeing closely with holotype in somatic features except stipital lobe much smaller, virtually nonexistent. Gynaspis ( Fig. 10 , G) large, expanding caudad into virtually an equivalent, parallel piece, extending for only short distance between valves; lobes deeply divided and distinct, medial corners prolonged and slightly indented. Lateral valve (LV) larger than medial, with lobe on outer/lateral margin and a few distal hairs obscured by gynaspis in caudal view; medial valve (MV) glabrous, semilunar.

Habitat. The specimens were recovered from a pitfall trap in a deciduous forest on a loess bluff bordering the eastern edge of the Mississippi/Yazoo River Delta region of Mississippi (T. L. Schiefer, personal communication). According to the website <http://www.marshdoc.com/physiography/physiography2/ physiography2.html>, loess bluffs arose from wind transport and deposition of silts from dust storms at the close of the Pleistocene. They are thickest on the western borders, where P. mississippiensis was taken, and are characterized by deeply dissected topography with steep-sided ravines and narrow ridges that give rise to diverse mesophytic forests dominated by hardwoods. The bluffs extend along the Mississippi River from Natchez to Vicksburg, then curve northeastward through Yazoo City, Grenada, and Charleston before returning to the River at Memphis, Tennessee; with seemingly ideal milliped habitat, they warrant thorough investigation in the future.

Distribution. Known only from the type locality, which lies some 220 mi (352 km) northwest of the closest generic record, P. o b t e c t u s in Mobile, Alabama.

Remarks. I discovered this sample in 1999 in the collection at the Mississippi Entomological Museum, Mississippi State University, Starkville, and the curator and collection manager graciously consented to its deposit in the NCSM.

As I have twice recently damaged or destroyed the "gonopodal regions" of male parajulids while attempting to dissect the gonopods, with holotypes of Arvechamboides ocala & P. mississippiensis , and could not completely describe them, it is timely to address the dissection process. While clues to an individual's identity and the likelihood of a new species can be gained from the nature of the epiproct and stipital lobes, the ventral configuration of the 8th sternum, aspects of the aperture, and any part of the gonopods that protrudes through the latter, these are at best vague; accurate determinations cannot be rendered until both pairs of gonopods are fully removed and viewed under a microscope. Parajulids thus differ from xystodesmids and other polydesmidans, where most if not all of the gonopods protrude externally and can be viewed in situ to determine if a new species is at hand. The rounded, cylindrical body form also causes difficulties because parajulids do not lie nicely on their dorsa with their ventral surfaces exposed as do "flat-backed" millipeds; to view parajulid venters, one must hold them in position either manually or place them on cotton, glass beads, etc. For dissection, I hold the specimen lightly with forceps in one hand and try to break the body between the 7th & 8th rings with forceps held in the other hand; when successful, the 8th sternum can be seen in situ in the caudal piece, and both pairs of gonopods can be extracted with a bent insect pin through the caudal end of the anterior piece. Sometimes both pairs of gonopods can be removed together and separated afterwards, while on others, one or both pgs can be removed first followed by the ags; careful dissection is necessary to avoid destroying the integrities of the gonopods and break fine structures like the pg prefemoral processes. On most occasions, however, the body does not break cleanly between the 7th & 8th rings (it crumbles, the exoskeleton tears, etc.), and one must then focus on extracting the gonopods without breakage and largely forget other features. Because they are the principal taxonomic structures, maintaining the integrities of the gonopods is overridingly important; if any feature must be sacrificed during dissection, it cannot be the gonopods without which authoritative determinations are impossible. The holotypes of P. mississippiensis and Arvechamboides ocala did not break cleanly between the 7th & 8th rings, and I had to focus on removing the gonopods without breakage at the expense of collateral structures; consequently, the 8th sternum of the former and the 7th pleurotergite of the latter will have to be characterized from additional males.

Figures

FIGURES 6 – 10. Pseudojulus mississippiensis, sexual features. 6, right anterior gonopod of holotype, anterior view. 7, the same, lateral view. 8, the same, caudal view. 9, left posterior gonopod of holotype, medial view. 10, cyphopods of female paratype, caudal view. ACL, anterior coxal lobe; AT, telopodite of anterior gonopod; G, gynaspis; LSP, lateral syncoxal process; LV, lateral valve; MV, medial valve; PFP, prefemoral process; PSL, posterior syncoxal lobes; PT, telopodite of posterior gonopod; S, sternum. Scale line = 0.75 mm for figs. 6 – 8 & 10, 0.50 mm for fig. 9.