Enghoffosoma extraspinosum, Gordana & Ambros, 2018

Enghoffosoma extraspinosum View in CoL sp.n.

Figs 4 View Figs 3–5 , 14–31 View Figs 14–17 View Figs 18–21 View Figs 22–25 View Figs 26–27 View Figs 28–31 .

HOLOTYPE ♂, Vietnam, Gia Lai Prov., Kon Ka Kinh National Park , N 14°12′43″, E 108°18′57″, 900 m a.s.l., mixed wet tropical forest at bottom of a river valley, on log, V.2017, leg. I.I. Semenyuk. GoogleMaps

PARATYPES: 3 ♂♂, 1 ♀, same data, together with holotype. GoogleMaps

DIAGNOSIS. Differs from other Enghoffosoma spp. primarily in the presence of an additional process ( a) on the gonopod.

NAME. To emphasize the presence of an additional process ( a) on the gonopod; adjective.

DESCRIPTION. Holotype and ♂ paratypes ca 21–22 mm long, width of midbody pro- and metazonae 2.6 and 3.0 mm, respectively. ♀ paratype ca 25 mm long, 3.0 and 3.4 mm wide on pro- and metazonae, respectively. General coloration in alcohol rather uniformly dark brown to brown, apparently somewhat faded, with a characteristic pattern of contrasting light creamy rear halves of paraterga and entire venter, legs light brown, tips of antennae pallid ( Figs 22– 25 View Figs 22–25 ). Live coloration darker, but pattern clear, blackish orange ( Fig. 4 View Figs 3–5 ).

Clypeolabral region densely setose, abundant small and a few longer setae between and above antennae, respectively; occipital region bare; epicranial suture thin, superficial ( Fig. 14 View Figs 14–17 ). Antennae long and slender, only slightly clavate ( Figs 22, 23 View Figs 22–25 ), in situ extending back behind segment 2 (♂) when stretched dorsally; in length, antennomeres 2–6 >> 1 = 7 ( Fig. 22 View Figs 22–25 ); interantennal isthmus about 1.1 times as broad as diameter of antennal socket ( Fig. 22 View Figs 22–25 ).

In width, head <segment 2 = 3 <collum = 4 <5–16; thereafter body gradually tapering towards telson ( Figs 22– 25 View Figs 22–25 ). Tegument nearly shining, almost dull; prozonae very finely shagreened; metaterga mostly smooth, longitudinally striolate in rear halves; surface below paraterga granulate and clearly striate longitudinally. Collum broadly rounded laterally, with small, subhorizontal, rounded, caudally subrectangular paraterga. Postcollum paraterga well-developed, mostly set low at about half of body height, oblique and clearly elevated caudally; caudal corner of paraterga 2 narrowly rounded, thereafter sharp, beak- or spine-shaped and drawn behind rear tergal margin ( Figs 22, 24, 25 View Figs 22–25 ), only paraterga 18 and 19 increasingly small ( Fig. 25 View Figs 22–25 ). Calluses delimited by a distinct sulcus only dorsally, particularly thin on poreless paraterga, somewhat thicker and slightly sinuate only in front of ozopore on pre-bearing paraterga. Ozopores small, lying inside short dorsolateral grooves, partly visible from above, located at about 1/4 off caudal corner ( Figs 22, 24, 25 View Figs 22–25 ). Transverse metatergal sulci absent, often with very faint impressions in their stead. Stricture between pro- and metazonae very thin and shallow, clearly beaded at bottom down to paraterga. Tergal setae largely abraded, short (about 1/4 of metatergal length, Fig. 24 View Figs 22–25 ), setation pattern traceable as 2+ 2 in a transverse row in anterior 1/3 of metaterga. Axial line missing. Pleurosternal carinae small flaps on segment 2, square ridges on segment 3, thereafter with an increasingly distinct caudal tooth until segment 7 (♂), then increasingly reduced on segments 8–16, traceable like small denticles even on segments 17–19 (♂) ( Fig. 22 View Figs 22–25 ) or 17–18 (♀). Epiproct rather long, coniform, subapical lateral papillae small, tip subtruncate ( Figs 22, 25 View Figs 22–25 ). Hypoproct roundly subtriangular, 1+1 setae strongly separated from each other, borne on minute knobs, clearly removed from caudal margin.

Sterna very densely setose, cross-impressions faint, axial impression especially poor; a very small, sharp, vestigial tubercle or cone near each coxa (♂); a low, setose, roundly subtrapeziform lobe between ♂ coxae 4. Legs long and slender, very densely setose, somewhat incrassate as compared to ♀, ca 1.5–1.6 (♂) or 1.1 –1.2 (♀) times as long as midbody height, devoid of adenostyles, ♂ prefemora clearly bulged laterally, tarsal brushes present only on ♂ legs 1–7, thereafter thinning out; in length, femora >> tarsi> tibiae = prefemora> postfemora = coxae (♂).

Gonopods ( Figs 23 View Figs 22–25 , 28–31 View Figs 28–31 ) rather complex, in situ slightly crossing each other distomedially; coxite about as long as femorite, subcylindrical, densely setose distolaterally; prefemoral (= densely setose) part of telopodite short, about 1/3 as long as acropodite; femorite ( fe) long, slender, untwisted, slightly enlarged apically only due to a short, but bulky postfemoral region ( pf); the latter set off basally from fe by an inconspicuous sulcus ( s) on mesal face and distally by a prominent apical shelf/cingulum ( b); pf with a single, distinct, dorsomesal, spine-shaped process ( p); base of a long, twisted, gradually attenuating solenomere ( sl) with two subequal membranous outgrowths, one ( e) axe-shaped and dorsomesal in position, the other ( a) spatuliform and ventromesal in location.

REMARKS. At the moment, the rather large Oriental genus Enghoffosoma Golovatch, 1993 encompasses 12 species described from Myanmar, Indochina and southern China [ Likhitrakarn et al., 2014; Nguyen, Golovatch, 2016; Golovatch et al., 2016]. The vivid colour pattern in E. extraspinosum sp.n. strongly resembles that observed in E. bispinum Likhitrakarn, Golovatch et Panha, 2014 , from Thailand, E. contrastum Golovatch, VandenSpiegel et Semenyuk, 2016 and E. digitatum Nguyen et Golovatch, 2016 , both from Vietnam, E. lanceolatum Likhitrakarn, Golovatch et Panha, 2014 , from both Thailand and Vietnam, and E. anchoriforme Likhitrakarn, Golovatch et Panha, 2014 , from both Laos and Vietnam [ Likhitrakarn et al., 2014; Nguyen, Golovatch, 2016; Golovatch et al., 2016], but they all are quite distinct in several somatic and, especially, gonopodal traits. Among congeners, the new species shows yet the maximum number (4) of clear-cut distal outgrowths on the gonopod.