Habeas centroris, Simone, 2022

Simone, Luiz Ricardo L., 2022, A new species of Habeas (Eupulmonata, Urocoptidae) from Canarana region, Bahia, Brazil, Papéis Avulsos de Zoologia (Pap. Avulsos Zool., S. Paulo) 62, pp. 1-8 : 2-5

Habeas centroris new species

( Figs. 1-23 ) https://zoobank.org/ 5B23C638-7D5B-4AAC-BB41-34C7B51366BB

Types: holotype MZSP 155200 . Paratypes: MZSP 153866 , 25 specimens, MNRJ 23646 , 2 specimens ; USNM, 2 specimens, all from type locality .

Type locality: BRAZIL. Bahia; Canarana, Paz de Salobro , 11°51′56″S, 41°45′07″W [W.Vailant-Mattos col., 20/iv/2021] .

Etymology: the specific epithet is a junction of the Latin words centro (center) and oris (mouth), an allusion to the central position of the peristome.

Diagnosis: Shell ~ 7 mm; inferior half almost cylindric; peristome relatively centrally positioned; umbilicus narrow; sculpture sense quantity of narrow and well-delimitated axial lines; rounded whorls profile. Pallial gland small. Ureteral groove well-marked, wide. Stomach short; duct to anterior lobe of digestive gland present. Seminal receptacle very small, always present; penis small, simple, lacking retractor muscle; vas deferens originating between posterior and middle thirds of spermoviduct; prostate lying anteriorly to vas deferens origin. Both visceral ganglia connected to pleural ganglia.

Description

Shell ( Figs. 1-9 , 11-14 ): Sinistral. Adult length ~ 7 mm, ~10 whorls; ~2.1 times longer than wide; apex angle ~60°, tip blunt; profile becoming almost cylindrical after ~5 whorls, with profile angle of ~20°. Color whitish ( Fig. 7 ), pale cream ( Figs. 6, 8 ) to pale beige ( Figs. 1-5 ). Protoconch with almost 4 smooth, opaque, rounded whorls ( Figs. 4 , 12 ); height = 0.8 mm, maximum width = 1 mm; occupying ~16% of total shell length, ~46% of shell width; transition with teleoconch relatively clear ( Figs. 3, 7 , 11-12 ). Teleoconch of 5.5-6 whorls; whorls profile rounded to slightly planar; ~4 last whorls almost similar-sized, weakly increasing ( Figs. 1-3, 6-8 , 11 )). Last half whorl weakly projected exteriorly, expanding shell width ~20% ( Figs. 1, 6-8 , 11 ); last ¼ whorl weakly dislocated inferiorly ( Figs. 3 , 13 ), bluntly angled, ending in external notch of outer lip. Sculpture uniform axial narrow ribs, interspaces twice wider than ribs; ~90 ribs in penultimate whorl; ribs density similar in all whorls. Peristome expanded, bugle-like, orthocline ( Figs. 2 , 13 ); complete ( Figs. 1, 6 , 11, 13 ) or with callus region weak ( Figs. 7, 8 ), slightly elliptic except for strong, wide notch in superior region of outer lip ( Figs. 1-2, 6-7 , 11, 13 ); peristome occupying ~22% of shell length, ~45% of shell width. Umbilicus of small size, occupying ~5% of inferior shell area ( Figs. 5, 9 ); umbilical hollow column lying uniformly all along inferior ¾ of teleoconch length ( Figs. 13, 14 : arrow).

Head-foot: Of ordinary shape, with similar feature of H. lekolus ( Simone, 2022) .

Pallial cavity ( Fig. 19 ): General organization similar to that of H.lekolus ( Simone,2022) ,distinctions and remarks following. Pallial gland (pg) present, but much smaller, occupying ~15% of entire mantle edge. Anus (an) opening very close to mantle edge. Inner pulmonary surface lacking developed vessels, uniformly smooth; rectum (rt) bulging along left edge, lacking developed adrectal sinus. Ureteral gutter (ur) wide, clearly running at right from rectum, from nephrostome (ne) up to pneumostome (pn). Reno-pericardial structures bulging in posterior half whorl, described below.

Visceral mass ( Fig. 20 ): Also with similar features as H. lekolus ( Simone, 2022) , differing mainly by minuteness of stomach (described below).

Circulatory and excretory systems ( Fig. 19 ): Mostly similar to those of as H. lekolus ( Simone, 2022) ; distinctions following. Pericardium (pc) and heart (au, ve) ~30% smaller; its pulmonary vein (cv) difficultly seen, lying along right pallial edge. Kidney (ki) mostly solid, white, antero-posteriorly shorter, slightly squared.

Digestive system ( Figs. 20-22 ): Most characters similar to those of H. lekolus ( Simone, 2022) ; remarkable and distinctive features following. Jaw plate ( Fig. 10 : jw) simple, thin, translucent, yellowish, smooth. Buccal mass ( Figs. 20-21 ) with pair m1d (dorsal protractor muscles) well-developed; pair m1l more ventrally positioned, thin, wider; pair m2 thinner ( Fig. 21 ); m3 lacking;internal organization, including oral cavity and odontophore, similar, except for narrower pair m5. Radula ( Figs. 15-18 ) composed of rachidian (arrows) plus ~15 pairs of lateral-marginal tooth, no clear separation of types ( Fig. 15 ); rachidian and lateral teeth with single, large curved cusp, longer and more pointed than those of H. lekolus ; rachidian occupying ~4% of radular ribbon width, ~30% narrower than neighboring teeth; lateral teeth 8-10 pairs, similar to rachidian except in being slightly wider and weakly turned outside ( Figs. 16, 18 ), gradually diminishing towards lateral; marginal teeth marked by gradual further diminish length, and appearance of more secondary cusps ( Fig. 17 ), in more central teeth small cusps appearing in medial side of main cusp, gradually cusps becoming smaller and same-sized towards lateral teeth, usually with 3 cusps.Lateral and marginal teeth performing wide curves (concavity posterior) in both sides of rachidian ( Fig. 15 ), curve more accentuated in marginals ( Fig. 17 ). Pair of salivary glands (sg) with shorter and broader ducts ( Fig. 21 : sd). Esophagus ( Fig. 20 : es) narrow, walls thin, internally smooth, after ~1.5 whorls esophagus gradually becoming weakly folded, with internal thick mucosa, up to left side of stomach. Stomach (st) small, as simple, swollen curve; esophageal insertion and intestinal origin side by side in its anterior side ( Fig. 20 ); anterior duct to digestive gland (dd) narrow, elongated, located in intersection between esophagus and intestine, turned anteriorly, slightly ventrally positioned; posterior duct to digestive gland slightly broader, located in right side of stomach, directed posteriorly.Digestive gland with anterior lobe (da) flattened, long, thin, compressed between local digestive tubes and columellar muscle. Intestine loops as in Fig. 20 ; narrow and relatively uniform along its length. Rectum and anus described above; rectum forming distinct squared fecal pellets ( Fig. 19 : fe), stored all along its length.

Genital system ( Fig. 22 ): General organization similar to that of H. lekolus ( Simone, 2022: figs. 19-20); distinctions and remarks following. Hermaphrodite duct (hd) simpler, narrow all along its length. Seminal receptacle (sr) very small,sac-like, always present.Albumen gland (ag) elliptical,~1/2 whorl in length.Spermoviduct (eo) of ~1.5 whorl in length, narrow, running close to diaphragm; uterus (ut) hollow, thick walled; and prostate (pt) mostly solid; both equally sized. Vas deferens (vd) originating in edge of prostate, about between posterior and middle thirds of spermoviduct; prostate further lying anteriorly about same length as posterior length.Vas deferens (vd) simple, thin, ~0.5 whorl in length; inserting after small curve in penis′ tip. Penis (pe) small, ~1/3 whorl,~twice longer than wide, weakly curved; tip blunt, strongly curved, epiphallus-like; no detectable penis retractor muscle, nor accessory genital muscle. Penis mostly hollow, inner arrangement with three narrow, equidistant longitudinal folds.

Central nervous system ( Fig. 23 ): Nerve ring, located anterior to buccal mass ( Fig. 21 ), with similar features of H. lekolus ( Simone, 2022: fig. 21); distinctions following. Cerebral commissure (cc) further longer. Cerebral glandular region not so clear. Pair of pleural ganglia (pl) also small, located equidistant from cerebral and pedal ganglia in both sides. Commissure between both pedal ganglia (pp) located more centrally, between both ganglia. Left visceral ganglion (gv) connected to adjacent pleural ganglion (instead of pedal ganglion). Pair of statocysts (sy) easily detectable, located in postero-ventral region of pedal ganglia.

Habitat: On calcareous rocks, crevices, and sheltered areas; dry vegetation.

Measurements (in mm): Holotype MZSP 155200 ( Figs. 1-5 ): 7.0 by 3.4; MZSP 153886 #1 ( Fig. 6 ): 6.8 by 3.2; #2 ( Fig. 7 ): 5.6 by 2.8; #3 ( Fig. 8 ): 5.9 by 3.0; #6 ( Fig. 11 ): 6.4 by 3.1. The paratypes 1, 2 and 3 have their shells posteriorly damaged, for specimen′s extraction.

Material examined: Types.

Figures

Figures 1-10. Habeas centroris shells of types:(1-5) Holotype MZSP 155200 (L 7.0 mm); (1) frontal view;(2) right view;(3) dorsal view;(4) apical view;(5) inferior view; (6) paratype MZSP 153866#1, frontal view (L 6.8 mm); (7) #2, frontal view (L 5.6 mm); (8) #3, frontal view (L 5.9 mm); (9) same, inferior view (W 3.0 mm); (10) buccal region,ventral view,with concern to jaw,scale 0.2 mm.

Figures 11-18. Habeas centroris SEM images of paratypes MZSP 153886 shells:(11) whole frontal view,specimen #6 (L 6.4 mm);(12) young specimen with protoconch and first teleoconch whorl,apical-slightly left view,scale = 200µm;(13)broken specimen #5,detail of last whorl,frontal-slightly rightview,scale = 400 µm; (14) same,higher magnification in penultimate whorl showing umbilicus (arrow); 15-18, radula,arrow showing rachidian column;(15) wide view,scale = 40 µm; (16) detail of central region,scale = 20 µm;(17) detail of lateral region,scale = 20µm;(18) detail of central region,scale = 5 µm.

Figures 19-20. Habeas centroris anatomical drawings: (19) pulmonary cavity and adjacent end of visceral mass, ventral view, ventral fold of pneumostome sectioned and deflected upwards;(20) uncoiled visceralmass,mostly ventral view,structures seen as insitu,anterior lobe of digestive glandremoved,buccal mass m2 also removed,some structures only indicated by their topology,anterior digestive tubes (located in haemocoel) still attached.Scales = 1 mm.

Figures 21-23.Habeas centroris anatomical drawings:(21) buccal mass,left view, left portion of m2 removed;(22) genital structures,uncoiled,mostly in ventral view,artificial section on middle region of spermoviduct done, topology of posterior lobe of digestive gland also shown;(23) central nervous system (nerve ring), dorsal view.Scales = 0.5 mm.