Xystopyge hippocampus, Enghoff, 2022

Enghoff, Henrik, 2022, Mountains of millipedes. The family Odontopygidae in the Eastern Arc Mountains of Tanzania (Diplopoda, Spirostreptida), European Journal of Taxonomy 803, pp. 1-136 : 113-116

Xystopyge hippocampus sp. nov.

urn:lsid:zoobank.org:act:DDCFB7F2-1F31-41EE-8939-EDDEAE26E48F

Figs 69–70

Diagnosis

Differs from other species of Xystopyge by the profile of the gonopod coxa and the shape of the terminal lobes of the telomere. The coxal profile reminds of that in X. enghoffi but in X. hippocampus sp. nov. the concavities on the mesal side are much deeper. Details of the terminal lobes have not been well described by previous authors, but apparently no other species has a seahorse-shaped lobe like that in X. hippocampus sp. nov.

Etymology

Named after the (somewhat) sea-horsehead like terminal telomeral lobe. Noun in apposition.

Material examined (total 1♂)

Holotype TANZANIA • ♂; Tanga Region, Muheza District , Manga FR ; 5°02′ S, 38°47′ E; 4 Aug. 1994; Frontier Tanzania leg.; plot 30:2; NHMD 621770 .

Description

(Only the head and the first 32 body rings are present)

SIZE. Diameter 3.5 mm.

COLOUR. After 26 years in alcohol uniform pale yellowish, traces of a narrow dorsal pale stripe present.

SUPRALABRAL SETAE. 6.

MANDIBULAR STIPES. Sub-rectangular, disto-ventrally rounded, diatal margin slightly sigmoid.

LIMBUS ( Fig. 69H ). Margin with smooth, rounded, finger-shaped lobes.

LEGS. With postfemoral and tibial pads from leg-pair 4.

FIRST PAIR OF LEGS ( Fig. 69A–C ). Prefemoral lobes short, almost semicircular in ventral view. Four long coxosternal setae (CXS) adjacent to lateral side of prefemoral process; prefemur with three mesapical setae (APS) and ca seven short lateral setae (LPS).

GONOPOD STERNUM (STERNUM 8). Tongue-shaped, ca twice as long as broad, slightly tapering towards emarginate tip, as in X. corolla VandenSpiegel & Pierrard, 2004¸but slightly stouter, cf. VandenSpiegel & Pierrard (2004: fig. 1).

STERNUM 9 ( Fig. 69I–J ). Transverse trapezoidal, ca twice as broad as long, with slightly concave diverging sides; apically with a pair of connected circular shallow pits separated by round bulges.

GONOPOD COXA ( Fig. 69D–G ). Proplica (PP) in anterior view almost parallel-sided, proplical lobe (PPL) duplicated, a blunt longitudinal ridge (lr) along mesal margin from PP; proplica in mesal view with a pair of thick, fingerlike bulges, one (fb1) curved, one (fb2) straight. Metaplica (MP) arched, with semicircular mesal incision, far overreaching proplica in the form of a somewhat bird-head-shaped cucullus (CU), at level of proplical lobe with oblique ridge (mor).

GONOPOD TELOPODITE ( Figs 69G , 70 ). Basomere (BA) of uniqiue specimen broken, see Fig. 69G . Arculus 135°. Torsotope not very well-delimited. Solenomere (SLM) almost as long as telomere, at rest nesting in hollow inner surface of the latter, in basal ¾ slender with a subcircular cross section; at base with stout, perpendicular basal spine (BSS); distally expanded and divided into a lamellate, pointed lobe (sdl) and a smooth pointed process (sdp). Telomere (TM) overall consisting of a ribbon describing a full circle and at the same time folded lengthwise forming a concavity along the inner side of the circle; without obvious processes, distal ¼ expanded, divided into two lobes delimiting a mesal window one (dtl1) simple, one (dtl2) sigmoid, spiculate along margin, vaguely resembling a sea-horse head.

Distribution and habitat

Known only from Manga FR in the East Usambara Mts. See Doggart et al. (1999) for information on this area. Found in same sample as X. voluntariorum sp. nov.

Figures

Fig. 69. Xystopyge hippocampus sp. nov., holotype, ♂ (NHMD 621770). A–C. First pair of legs. A. Sublateral view. B. Ventral view. C. Anterior view. D–G. Left gonopod coxa. D. Apical (ventral) view. E. Anterior view. F. Posterior view. G. Mesal view. H. Midbody dorsal limbus. I–J. Sternum 9. I. Posterior view. J. Subapical (subventral) view. Abbreviations: APS=mesapical prefemoral setae; BA = basomere of telopodite (broken); CU =cucullus; CXS = coxosternal setae; fb1, fb2 =fingerlike proplical bulges; LPS =lateral prefemoral setae; lr=longitudinal proplical ridge; mor=metaplical oblique ridge; MP=metaplica; PP =proplica; PPL =proplical lobe. Scale bars. A–G, I–J =0.2 mm; H =0.01 mm.

Fig. 70. Xystopyge hippocampus sp. nov., holotype, ♂ (NHMD 621770). A–G. Left gonopod telopodite. A. Anterior view. B. As A, close-up of tip. C. Posterior view. D. Ventral view. E. Dorsal view. F. Mesal view. G. Dorso-mesal view, close-up of tip. H. Right solenomere, tip. Abbreviations: BSS =basal solenomeral spine; dtl1, dtl2 =distal telomeral lobes; sdl=soloenomeral distal lobe; sdp=solenomeral distal process; SLM=solenomere; TM =telomere. Scale bars: A, C–F =0.2 mm; B, G =0.1 mm; H not to scale.