Vinaphilus unicus, Thi Thanh Tran, Binh, Thi Xuan Tran, Hoa & Bonato, Lucio, 2019

Thi Thanh Tran, Binh, Thi Xuan Tran, Hoa & Bonato, Lucio, 2019, A new soil centipede from South-East Asia with a unique arrangement of ventral glands, and a revised synopsis of Gonibregmatidae (Chilopoda, Geophilomorpha), ZooKeys 838, pp. 111-132 : 113-118

Vinaphilus unicus sp. n. Figs 1, 2, 3

Material examined.

Holotype: IEBR-Chi 001, ♀, 65 mm long, with 109 leg-bearing segments, with developed gonopods; in ethanol 70%; collected by Anh D. Nguyen, 11-19 September 2016, originally labelled ML01a; originally entire, subsequently divided into four pieces (cephalic capsule with right mandible and part of maxillae; left mandible; left half of the second maxillae; trunk); in the Department of Zoological Museum, Institute of Ecology and Biological Resources, Vietnam Academy of Science and Technology.

Paratype: PD-G 9530, ♀, 90 mm long, with 109 leg-bearing segments, with developed gonopods; in ethanol 70%; collected together with the holotype, same date and locality, originally labelled ML01a1; entire; in the Department of Biology, University of Padova.

Type locality.

Vietnam: Vinh Phuc province: Ngoc Thanh commune: Me Linh Station for Biodiversity: 21°23'42"N, 105°42'48"E; 150 m a.s.l.; secondary forest.

Diagnosis.

A Vinaphilus species with the following characters: body length up to> 8 cm; head about as long as wide, lacking transverse suture; antenna about 3 times as long as the head, with intermediate articles about as long as wide; most clypeal setae located in a broad subtriangular medial area, a few other setae close to the mid-point of the anterior margin and in 2 anterolateral groups; intermediate labral projections darker, shorter and closer to each other than lateral projections; forcipular coxosternite> 1.5 times as wide as long, with incomplete chitin-lines; trochanteroprefemur much wider than long; tarsungulum ca 2 times as long as the trochanteroprefemur, with finely serrate internal margin; poison calyx elongated; trunk tergites and sternites wider than long; around 109 pairs of legs, with 2 accessory spines; paired pore-fields of the sternites gradually changing from circular to longitudinally elongated along the trunk, but missing on the first and the prepenultimate leg-bearing segment; medial pore-field of the sternites subcircular, present also on the first and the prepenultimate leg-bearing segment; most of the coxal pores covered by the metasternite of the ultimate leg-bearing segment, a few anterior pores on the lateral side of coxopleuron and a single posterior pore isolated on the ventral side; metasternite of the ultimate leg-bearing segment subtrapezoidal, wider than long; ultimate telopodite ca 2 times as long as the penultimate, with a small terminal spine.

Name derivation.

A Latin adjective “unicus”, to emphasize the unique arrangement of the ventral glandular pores.

Description of holotype.

General features (Fig. 1 A–C). Body 65 mm long, depressed, almost uniformly wide along the trunk (ca 1.3 mm) but slightly narrowing posteriorly (penultimate leg-bearing segment 0.8 mm wide). Color (in ethanol) uniformly light yellow, but head and forcipular segment slightly darker.

Cephalic capsule (Fig. 2A, B). Cephalic plate sub-heptagonal, about as long as wide, lateral margins more distinctly converging anteriorly than posteriorly, posterior margin straight; scutes approximately isometric and up to ca 10 μm; transverse suture absent; setae up to ca 100 μm long. Clypeus ca 2.7 times as wide as long, with lateral margins complete; uniformly areolate, with scutes ca 10 μm wide; no obvious clypeal areas; at least 56 setae, all in the anterior half of the clypeus, most of them in a subtriangular intermediate broad area, ca 9 setae in each of 2 anterolateral smaller areas, and a few other apparently broken setae close to the mid-point of the anterior margin of the clypeus. Pleurites uniformly areolate, with 15-17 setae each. Labral margin slightly concave, with a row of 30 projections, including 8 intermediate denticles that are darker, shorter and closer to each other than the lateral projections.

Antenna (Fig. 1A, B). 14 articles. Entire antenna ca 2.7 times as long as the head width. Intermediate articles about as long as wide. Article XIV ca 2.1 times as long as wide, ca 1.6 times as long as article XIII, and twice the length of intermediate articles. Setae gradually denser from article I to X on the dorsal side, from article I to V on the ventral side, almost completely missing on the ventral-internal side of articles I–V, however uniformly dense in the remaining distal articles. Setae gradually shorter from article I to about V, up to 100 μm long on article I and <40 μm long on article XIV. Apical sensilla ca 10 μm long, spear-like, without projections, distinctly narrowing at about the mid-length. Club-like sensilla ca 10 μm long, grouped on the distal parts of the internal sides of articles IX–XIV and on the distal parts of the external sides of articles V–XIV. Three longitudinal rows of 1-5 proprioceptive spine-like sensilla at the bases of the antennal articles, approximately dorsal, ventro-internal and ventro-external; rows reduced to 0-1 spine on antennal articles VI, X and XIV. A few sensilla, similar to the apical ones but slightly darker and shorter, up to 5 μm long, on both dorso-external and ventro-internal position, close to the distal margin of articles II, V, IX and XIII.

Mandible (Fig. 2C, D). A single pectinate lamella, with 20-30 elongate teeth. Each tooth about 5 times as long as wide.

First maxillae (Fig. 3A). Coxosternite entire, with setae close to the anterior margin; a pair of lappets, covered with scales. Coxal projection subtriangular, longer than wide, with setae on the ventral side. Telopodite longer than wide, of 2 articles, with setae on the ventral side; a lappet emerging from the basal article and covered with scales.

Second maxillae (Fig. 3B). Coxosternite entire, with anterior margin deeply angulated, metameric pores on the central part of each half and about 7 setae near each of the posterior corners. Telopodite of 3 articles, slightly narrowing towards the tip; a number of setae on each article, most of them on the meso-ventral side; pretarsus ca 0.4 times as long as the distal article, slightly bent, narrowing and slightly spoon-shaped at the tip, with 7 filaments along the dorsal edge and 7 filaments along the ventral edge; 4 pore-like sensilla on each pretarsus, 1 on the convex side, 3 on the concave side.

Forcipular segment (Fig. 2A, E). Tergite subtrapezoidal, ca 2.8 times as wide as long, with lateral margins strongly converging anteriorly, approximately as wide as the cephalic plate and ca 0.9 times as wide as the following tergite. Exposed part of the coxosternite ca 1.6 times as wide as long; anterior margin with a shallow medial concavity and without denticles; complete coxopleural sutures, entirely ventral, sinuous and diverging anteriorly; chitin-lines incomplete, only visible in the posterior part of the coxosternite. Basal distance between the forcipules ca 0.4-0.5 times of the maximum width of the coxosternite. Trochanteroprefemur ca 1.4 times as wide as long. Intermediate articles distinct. No denticles along the forcipule. Tarsungulum ca 2.8 times as long as wide, ca 2.2 times as long as the trochanteroprefemur; both the external and the internal margins uniformly curved, except for a moderate mesal basal bulge; ungulum not distinctly flattened, internal margin serrated with ca 40 small notches. Elongated poison calyx, ca 5-6 times as long as wide, lodged inside the intermediate forcipular articles.

Leg-bearing segments (Figs 1, 3C, 4). A total of 109 pairs of legs. Metatergite 1 slightly wider than the subsequent one, without pretergite. No paratergites. Walking legs shorter than the width of the trunk; legs of the first pair slightly smaller than the following ones; claws simple, uniformly bent, with 2 accessory spines, the anterior spine reaching at most 20% of the length of the claw, the posterior spine much shorter. Metasternites ca 2 times as wide as long in the anterior part of trunk, up to 1.3 times as wide as long in the posterior part. Ventral glandular pores densely grouped into 3 separate fields on each metasternite, from the second to the prepenultimate leg-bearing segments: 2 paired fields in the anterior part of the metasternite, close to the lateral margins, subcircular and closer to the anterior corners in the most anterior segments longitudinally slightly elongated and closer to mid-length along the remaining trunk; 1 subcircular medial field approximately in the centre of the metasternite in the anterior part of the body, gradually becoming closer to the posterior margin in the most posterior segments. Only the medial field on the first and the penultimate leg-bearing segment.

Ultimate leg-bearing segment (Figs 1C, 3D). Pleuropretergite entire, without sulci. Metatergite subtrapezoidal, ca 1.2 times as wide as long, lateral margins convex and converging posteriorly, posterior margin slightly curved. Coxopleuron ca 1.5 times as long as the metasternite. Coxal organs of each coxopleuron opening through about 30 independent pores, mostly clustered and covered by the metasternite, but 2 or 3 pores on the lateral side of the coxopleuron, including 1 pore on the posterior third of the ventral side of the coxopleuron. Metasternite subtrapezoidal, wider than long, anteriorly ca 2.6 times as wide as posteriorly, lateral margins slightly convex and converging backwards; setae denser on 2 broad lateral parts of metasternite, almost absent close to the posterior margin and in a narrower mid-longitudinal stripe. Telopodite approximately 11 times as long as wide, ca 1.8 times as long and ca 1.8 times as wide as the penultimate telopodite; 6 articles; tarsus 2, ca 2.7 times as long as wide and ca 0.7 times as long as tarsus 1; uniformly dense setae, <45 μm long, on most of the ventral and dorsal sides of the telopodite. Pretarsus absent, a small spine in its place.

Postpedal segments (Fig. 3D). Two gonopods, basally touching, subtriangular, without traces of articulation, covered with setae. Anal organs apparently absent.

Main differences of paratype.

Entire antenna ca 2.9 times as long as the head width; intermediate articles ca 1.1 times as long as wide; article XIV ca 2.0 times as long as wide and ca 1.5 times as long as article XIII. Exposed part of the forcipular coxosternite ca 1.7 times as wide as long; tarsungulum ca 1.8 times as long as the trochanteroprefemur. Metasternites ca 3 times as wide as long in the anterior part of trunk, up to 1.4 times as wide as long in the posterior part. About 40 coxal pores on each coxopleuron. Telopodite of the ultimate pair of legs approximately 13 times as long as wide, ca 2.3 times as long and ca 1.4 times as wide as the penultimate telopodite.