Siphonophora hebetunguis
Creators: name: Read, Helen J.
name: Enghoff, Henrik
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Diplopoda
Siphonophorida
Siphonophoridae
Siphonophora
Siphonophora hebetunguis

description: Siphonophora hebetunguis (Attems, 1951)
Figs 1–2, 9A
Rhinosiphora hebetunguis Attems, 1951: 228.
Siphonophora hebetunguis – Jeekel 2001: 59.
Diagnosis
Small, pale species with paddle-shaped claws, generally very tuberculate on head, collum, metazonites and coxae. Ventral margin of pleurites almost straight, hind margin with some tubercles. Accessory claw short and arising from lateral side of the claw. Anterior gonopods short and squat, with no spines or other structures at the tip.
Etymology
A noun in apposition from the Latin ‘ hebe ’, meaning ‘blunt’ or ‘dull’ and ‘ unguis ’, meaning ‘claw’ and referring to the shape of the claw. Note that in the original description the spelling hebetungis appears, although the key and figure legends use the spelling hebetunguis. The type series from Vienna is labelled hebetungis. As ‘ unguis ’ means ‘claw’ and the claw shape is referred to in the description, it appears that the use of ‘ hebetungis ’ is probably a lapsus calami and that the spelling hebetunguis can be taken as correct.
Material examined
None of the material is labelled as types, and all the specimens should be considered as syntypes. Two microscope slides, containing the head, first seven body rings, telson, and anterior and posterior gonopods, in combination with a separate body in fluid, constitute a potential lectotype, but we refrain from formally designating it as such. The original description does not list the number of specimens, although both males and females were obviously present.
BRAZIL • 6 ♂♂, 2 ♀♀; ‘Brasilien, Taperinha près Santarem. Coll Zerny’; NHMW 2295.
Redescription
Mostly made from the non-mounted specimens, as the slides are so cleared that most structures are not easily visible.
MEASUREMENTS. Body length: ♂: 5.2–11.25 mm, ♀: 15–17 mm. Body width: ♂: 0.54–0.64 mm, ♀: 0.88 mm. Number of podous tergites: ♂: 33–50, ♀: 57–62. Number of apodous tergites: ♂: 0, ♀: 1–2.
COLOUR. Pale cream (but may be due to state of preservation).
BODY SHAPE. More or less parallel-sided.
HEAD. In dorsal view showing sinuous or stepped outline laterally between antennal bases and base of rostrum. In lateral view almost flat, with slight demarcation between rostrum and rest of head. Rostrum very slightly downwardly curved. Length of rostrum (to antennal base): ♂: 0.34–0.56 mm, ♀: 0.42– 0.56 mm. Width of head (between antennal sockets): ♂: 0.20 mm, ♀: 0.24–0.26 mm. Abundant setae and tubercles on head. Long setae on gnathochilarium at base of rostrum, some of which reach to rostrum tip.
ANTENNAE. Appearing more or less the same length as rostrum but exact length not analysed, nor length:width ratio of segments. Sensory pits on antennomeres 5 and 6 present but not especially clear or large.
COLLUM. Wide, anterior margin with a gentle curve for anterior margin (not examined in SEM). Posterior margin more or less straight. With abundant setae and tubercles.
TERGITE 2. More than 0.5 × length of collum.
MID- BODY RINGS. When plotted (Fig. 1) this species has a small body size and relatively few rings in the males, but there are not enough females to give a clear picture. Paranota not obvious. Slightly castellated, especially anteriorly. Relative width of pro- and metazonites 0.83–0.95. Prozonites with tubercles, but no setae, metazonites with abundant setae, none long, and tubercles. Prozonite with a channel-like area just in front of the border with the metazonite. Limbus very clearly crenulated under SEM. Ventral margin of pleurites almost straight, although with slightly bilobed margin in anterior few rings. Hind edge of pleurite from inside with clear but irregular tubercles, not serrate but with some setae. Ozopores very difficult to see. The original description does not report on which ring they start, but they were said to be on small protuberances; this may well be due to the state of preservation. In specimens viewed here, the protuberances were not obvious.
LEGS. Length relative to body height and length:width ratio of podomeres not analysed. Coxae tuberculate. Claw broadly expanded and paddle-shaped on anteriormost legs of males and females; by approximately leg pair 80 becoming more conventionally claw-shaped. Accessory claw: short, ¼–½ length of claw, quite broad and with rounded tip, arising from lateral side of claw.
TELSON. Length:width ratio 0.42–0.6.
ANTERIOR MALE LEGS (pairs 1–8). Appear normal.
ANTERIOR GONOPODS (Fig. 2D). Short and squat, with segments evidently fused together so exact number is difficult to see. Pair of gonopods appearing like two cupped hands with the cup facing ventrad. Ventral surface with setae but lateral surface without. No apparent enlarged setae or other structures at tip of anterior gonopods, including in slide-mounted syntype (note that in those illustrated in Fig. 2D tip of a posterior gonopod protrudes, looking like a structure at tip of anterior gonopods).
POSTERIOR GONOPODS. Not visible in situ in any specimens but original illustrations showed it to be of ‘typical’ siphonophorid type with last segment long, thin, with spine towards base and a simple doublepointed tip. Slide mount shows spine, although tip is not clear.
Remarks
All specimens were found at the same time of the year at the same location. The original description of R. hebetunguis describes ozopores situated on slight protuberances. However, in all the species described here (and in species of Columbianum as well, Read & Enghoff 2018) the ozopores are surrounded by a ring of setae. As noted earlier, this can sometimes give the appearance of the ozopores protruding. Examination of various species in the Natural History Museum in London revealed some with clear paranota, for example S. longirostris Silvestri, 1895, unlike in any of those in the current collection. See Table 1 for a comparison of the features of S. hebetunguis and the other species of Siphonophora from Brazil, as well as S. portoricensis Brandt, 1837.
The new species described below differ from S. hebetunguis in the structure of the anterior gonopods as well as in some other somatic characters. They do, however, have claws that are shaped similar to those described for hebetunguis.
description: Published as part of Read, Helen J. & Enghoff, Henrik, 2019, Siphonophoridae from Brazilian Amazonia. Part 2 - Two new treeclimbing species of the genus Siphonophora, including one showing pilosity polymorphism (Diplopoda, Siphonophorida), pp. 1-26 in European Journal of Taxonomy 496 on pages 3-8, DOI: 10.5852/ejt.2019.496, http://zenodo.org/record/2561752